@article{8338141,

title = {Adaptive Layout Technique for Microhybrid Integration of Chip-Film Patch},

author = {G Alavi and H Sailer and B Albrecht and C Harendt and J N Burghartz},

doi = {10.1109/TCPMT.2018.2818762},

issn = {2156-3950},

year  = {2018},

date = {2018-05-01},

journal = {IEEE Transactions on Components, Packaging and Manufacturing Technology},

volume = {8},

number = {5},

pages = {802-810},

abstract = {In this paper, a unique adaptive layout methodology for accurate interconnection between two or more functional chips at the wafer level is presented. The methodology is based on an automatic layout modification for each embedded chip with considering exact related offset and rotation after chip embedding. As a result, a wafer-level embedding and accurate interconnecting and integrating of ultrathin chips in the polymer are feasible. The significant application of the presented accurate interconnection between the groups of functional chips is the microhybrid system-in-foil. Also, an adaptive interconnect layout at wafer-level base, allowing for a small wire pitch on and off the chip, leads to reducing silicon area and, thus, saves cost. In this paper, the process flow for embedding and integrating chips based on the adaptive layout technique is presented. The custom designed test chips are processed for the measurement and optimization of overlay accuracy of the adaptive interconnect layout regardless of the chip thickness, warpage, and topography. Besides, the electrical measurements after integrating ultrathin chips in foil confirm the interconnection between chips.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{AlvaradoChavarin2018.ma11030345,

title = {Current Modulation of a Heterojunction Structure by an Ultra-Thin Graphene Base Electrode},

author = {Carlos Alvarado Chavarin and Carsten Strobel and Julia Kitzmann and Antonio Di Bartolomeo and Mindaugas Lukosius and Matthias Albert and Johann Wolfgang Bartha and Christian Wenger},

url = {https://www.mdpi.com/1996-1944/11/3/345},

doi = {10.3390/ma11030345},

issn = {1996-1944},

year  = {2018},

date = {2018-02-01},

journal = {Materials},

volume = {11},

number = {3},

abstract = {Graphene has been proposed as the current controlling element of vertical transport in heterojunction transistors, as it could potentially achieve high operation frequencies due to its metallic character and 2D nature. Simulations of graphene acting as a thermionic barrier between the transport of two semiconductor layers have shown cut-off frequencies larger than 1 THz. Furthermore, the use of n-doped amorphous silicon, (n)-a-Si:H, as the semiconductor for this approach could enable flexible electronics with high cutoff frequencies. In this work, we fabricated a vertical structure on a rigid substrate where graphene is embedded between two differently doped (n)-a-Si:H layers deposited by very high frequency (140 MHz) plasma-enhanced chemical vapor deposition. The operation of this heterojunction structure is investigated by the two diode-like interfaces by means of temperature dependent current-voltage characterization, followed by the electrical characterization in a three-terminal configuration. We demonstrate that the vertical current between the (n)-a-Si:H layers is successfully controlled by the ultra-thin graphene base voltage. While current saturation is yet to be achieved, a transconductance of ~230 μ S was obtained, demonstrating a moderate modulation of the collector-emitter current by the ultra-thin graphene base voltage. These results show promising progress towards the application of graphene base heterojunction transistors.},

keywords = {},

pubstate = {PubMed-not-MEDLINE},

tppubtype = {article}

}

@article{ZSCHIESCHANG201865,

title = {Stencil lithography for organic thin-film transistors with a channel length of 300 nm},

author = {Ute Zschieschang and James W Borchert and Michael Geiger and Florian Letzkus and Joachim N Burghartz and Hagen Klauk},

url = {http://www.sciencedirect.com/science/article/pii/S1566119918303446},

doi = {https://doi.org/10.1016/j.orgel.2018.06.053},

issn = {1566-1199},

year  = {2018},

date = {2018-01-01},

journal = {Organic Electronics},

volume = {61},

pages = {65 - 69},

abstract = {For some of the more demanding applications envisioned for organic transistors, lateral device dimensions of less than 1 μm may be necessary or should at least be explored in order to evaluate the scalability of organic transistors. Using stencil lithography based on high-resolution silicon stencil masks and employing two small-molecule organic semiconductors with good long-term air stability, we have fabricated organic p-channel and n-channel transistors with a channel length of 0.3 μm. Owing to the small channel length, the transistors have large channel-width-normalized transconductances (1.5 S/m for the p-channel and 0.2 S/m for the n-channel transistors). In addition, the transistors have steep subthreshold slopes (80 and 200 mV/decade) and large on/off current ratios (106).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1063/1.5038941,

title = {MESFETs and inverters based on amorphous zinc-tin-oxide thin films prepared at room temperature},

author = {Sofie Vogt and Holger von Wenckstern and Marius Grundmann},

url = {https://doi.org/10.1063/1.5038941},

doi = {10.1063/1.5038941},

year  = {2018},

date = {2018-01-01},

journal = {Applied Physics Letters},

volume = {113},

number = {13},

pages = {133501},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kheradmand-Boroujeni2018.DOISTART,

title = {A Pulse-Biasing Small-Signal Measurement Technique Enabling 40 MHz Operation of Vertical Organic Transistors},

author = {Bahman Kheradmand-Boroujeni and Markus P Klinger and Axel Fischer and Hans Kleemann and Karl Leo and Frank Ellinger},

url = {https://doi.org/10.1038/s41598-018-26008-0},

issn = {2045-2322},

year  = {2018},

date = {2018-01-01},

journal = {Scientific Reports},

volume = {8},

number = {1},

pages = {7643},

abstract = {Organic/polymer transistors can enable the fabrication of large-area flexible circuits. However, these devices are inherently temperature sensitive due to the strong temperature dependence of charge carrier mobility, suffer from low thermal conductivity of plastic substrates, and are slow due to the low mobility and long channel length (L). Here we report a new, advanced characterization circuit that within around ten microseconds simultaneously applies an accurate large-signal pulse bias and a small-signal sinusoidal excitation to the transistor and measures many high-frequency parameters. This significantly reduces the self-heating and therefore provides data at a known junction temperature more accurate for fitting model parameters to the results, enables small-signal characterization over >10 times wider bias I-V range, with ~105 times less bias-stress effects. Fully thermally-evaporated vertical permeable-base transistors with physical L = 200 nm fabricated using C60 fullerene semiconductor are characterized. Intrinsic gain up to 35 dB, and record transit frequency (unity current-gain cutoff frequency, fT) of 40 MHz at 8.6 V are achieved. Interestingly, no saturation in fT − I and transconductance (gm − I) is observed at high currents. This paves the way for the integration of high-frequency functionalities into organic circuits, such as long-distance wireless communication and switching power converters.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{C8CP00544C,

title = {Charge carrier mobility of disordered organic semiconductors with correlated energetic and spatial disorder},

author = {Waldemar Kaiser and Tim Albes and Alessio Gagliardi},

url = {http://dx.doi.org/10.1039/C8CP00544C},

doi = {10.1039/C8CP00544C},

year  = {2018},

date = {2018-01-01},

journal = {Phys. Chem. Chem. Phys.},

pages = {-},

publisher = {The Royal Society of Chemistry},

abstract = {Low charge carrier mobility is one key factor limiting the performance and applicability of devices based on organic semiconductors. Theoretical studies on the mobility using kinetic Monte Carlo or Master equation are mainly based on a Gaussian energetic disorder and regular cubic lattices. The dependence of the mobility on the electric field, temperature and charge carrier density is well studied for the Gaussian disorder model. In this work, we investigate the influence of spatially correlated site energies and spatial disorder in the lattice sites on the mobility using kinetic Monte Carlo simulations. Our analysis is based on both a regular cubic and a non-cubic Voronoi lattice. The latter is used to include spatial disorder in order to study its influence on the mobility for amorphous organic materials. Our results show, that the charge carrier mobility is strongly influenced by correlations in the site energies. Strong correlations even invert the field dependence of the mobility as observed experimentally in semi-crystalline polymers such as P3HT. Evaluation of local currents between localized states reveals the formation of current filaments with rising correlation. Furthermore, the influence of the electric field and the energy landscape on the transport energy is studied by evaluation of active sites. A strong correlation between the transport energy, filaments in the local currents and the charge carrier mobility is observed. Our studies on the spatial disorder model do not indicate an inversion of the field dependence as observed by other researchers. The negative field-dependence in semi-crystalline materials may be explained by a higher correlation in the site energies as shown in the strongly correlated energetic landscape.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{8268674,

title = {Zero-Bias 50-dB Dynamic Range Linear-in-dB V-Band Power Detector Based on CVD Graphene Diode on Glass},

author = {M Saeed and A Hamed and Z Wang and M Shaygan and D Neumaier and R Negra},

doi = {10.1109/TMTT.2018.2792439},

issn = {0018-9480},

year  = {2018},

date = {2018-01-01},

journal = {IEEE Transactions on Microwave Theory and Techniques},

volume = {PP},

number = {99},

pages = {1-7},

abstract = {In this paper, we report the design, fabrication, and demonstration of a compact, V-band, zero-bias, and linear-in-dB power detector based on our in-house metal-insulator-graphene diode fabricated on a glass substrate. The presented circuit is optimized for the frequency band of 40-75 GHz. The measured prototype shows a repeatable measured dynamic range of at least 50 dB with down to -50 dBm sensitivity on 500-μm-thick quartz substrate. It also shows input return loss better than -9.5 dB over the entire design bandwidth. The measured tangential responsivity for the fabricated circuit on glass is 168 V/W at 2.5 GHz and 15 V/W at 60 GHz. The obtained results together with the robust device fabrication based on chemical vapor deposition graphene promote the proposed scheme and device for repeatable, statistically stable millimeter-wave, and submillimeter-wave applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{C7NR06871A,

title = {Graphene integrated circuits: new prospects towards receiver realisation},

author = {Mohamed Saeed and Ahmed Hamed and Zhenxing Wang and Mehrdad Shaygan and Daniel Neumaier and Renato Negra},

url = {http://dx.doi.org/10.1039/C7NR06871A},

doi = {10.1039/C7NR06871A},

year  = {2018},

date = {2018-01-01},

journal = {Nanoscale},

volume = {10},

pages = {93-99},

publisher = {The Royal Society of Chemistry},

abstract = {This work demonstrates a design approach which enables the fabrication of fully integrated radio frequency (RF) and millimetre-wave frequency direct-conversion graphene receivers by adapting the frontend architecture to exploit the state-of-the-art performance of the recently reported wafer-scale CVD metal-insulator-graphene (MIG) diodes. As a proof-of-concept, we built a fully integrated microwave receiver in the frequency range 2.1-2.7 GHz employing the strong nonlinearity and the high responsivity of MIG diodes to successfully receive and demodulate complex, digitally modulated communication signals at 2.45 GHz. In addition, the fabricated receiver uses zero-biased MIG diodes and consumes zero dc power. With the flexibility to be fabricated on different substrates, the prototype receiver frontend is fabricated on a low-cost, glass substrate utilising a custom-developed MMIC process backend which enables the high performance of passive components. The measured performance of the prototype makes it suitable for Internet-of-Things (IoT) and Radio Frequency Identification (RFID) systems for medical and communication applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{SUN20188,

title = {Influence of acceptor on charge mobility in stacked π-conjugated polymers},

author = {Shih-Jye Sun and Miroslav Men\v{s}\'{i}k and Petr Toman and Alessio Gagliardi and Karel Kr\'{a}l},

url = {http://www.sciencedirect.com/science/article/pii/S0301010417308224},

doi = {https://doi.org/10.1016/j.chemphys.2017.11.016},

issn = {0301-0104},

year  = {2018},

date = {2018-01-01},

journal = {Chemical Physics},

volume = {501},

pages = {8 - 14},

abstract = {We present a quantum molecular model to calculate mobility of π-stacked P3HT polymer layers with electron acceptor dopants coupled next to side groups in random position with respect to the linear chain. The hole density, the acceptor LUMO energy and the hybridization transfer integral between the acceptor and polymer were found to be very critical factors to the final hole mobility. For a dopant LUMO energy close and high above the top of the polymer valence band we have found a significant mobility increase with the hole concentration and with the dopant LUMO energy approaching the top of the polymer valence band. Higher mobility was achieved for small values of hybridization transfer integral between polymer and the acceptor, corresponding to the case of weakly bound acceptor. Strong couplings between the polymer and the acceptor with Coulomb repulsion interactions induced from the electron localizations was found to suppress the hole mobility.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{OZBEK2018291,

title = {3-Path SiGe BiCMOS power amplifier on thinned substrate for IoT applications},

author = {Sefa \"{O}zbek and Golzar Alavi and Johannes Digel and Markus Gr\"{o}zing and Joachim N Burghartz and Manfred Berroth},

url = {http://www.sciencedirect.com/science/article/pii/S016792601730634X},

doi = {https://doi.org/10.1016/j.vlsi.2018.04.010},

issn = {0167-9260},

year  = {2018},

date = {2018-01-01},

journal = {Integration},

volume = {63},

pages = {291 - 298},

abstract = {This paper reports a transformer-based integrated class-A Differential Power Amplifier (DPA) for the Internet of Things (IoT) applications. The proposed 5\textendash6 GHz fully integrated differential PA is fabricated in a cost-effective 95 GHz-fmax, 0.25 μm SiGe BiCMOS technology (IHP process SGB25V). The amplifier utilizes a thin Si chip with a thickness of 45 μm in order to be embedded into flexible electronic foil systems. Several key RF performance parameters of the DPA with different substrate thicknesses are evaluated at the wafer level. The measurement results indicate that the DPA shows no significant S-parameters degradation due to the thickness differences. The measured gain center frequency is shifted about 300 MHz towards higher frequencies after thinning because of the image mirror currents within the conducting material at the backside of the chip. The DPA achieves 10.65 dB and 9.7 dB small-signal gain at 5.5 GHz before and after thinning, respectively. The PA delivers an output power of +9 dBm before and +8.1 dBm after thinning process at Pin = −1.3 dBm. The simulated 1 dB compression point occurs at +10.76 dBm output power with a PAE of 15%.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{JOSHI201887,

title = {Understanding the influence of in-plane gate electrode design on electrolyte gated transistor},

author = {Saumya Joshi and Vijay Deep Bhatt and Himanshi Rani and Markus Becherer and Paolo Lugli},

url = {http://www.sciencedirect.com/science/article/pii/S0167931718303630},

doi = {https://doi.org/10.1016/j.mee.2018.07.019},

issn = {0167-9317},

year  = {2018},

date = {2018-01-01},

journal = {Microelectronic Engineering},

volume = {199},

pages = {87 - 91},

abstract = {Present work investigates the influence of gate electrode design in performance of electrolyte-gated carbon nanotube transistors. Electrolyte gated transistors have a huge potential in biological and chemical sensing. Recently, in-plane gate electrode has replaced the earlier used gate electrode wire in these systems. It becomes extremely essential to investigate the impact of gate electrode design on the device properties, and to optimize the electrode design to harness maximum sensitivity and speed. As a part of this work we have investigated the impact of gate electrode area and the distance between the gate electrode and the channel on the transistor characteristics. Area of gate electrode scales almost linearly with the drain to source current. However, the dependence of the gate distance is highly affected by experimental factors. Random network of carbon nanotubes serve as the semicondutor channel for electrolyte gated field effect transistors under study.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Joshi2018b,

title = {Ambient Processed, Water-Stable, Aqueous-Gated sub 1 V n-type Carbon Nanotube Field Effect Transistor},

author = {Saumya Joshi and Vijay Deep Bhatt and Ewa Jaworska and Agata Michalska and Krzysztof Maksymiuk and Markus Becherer and Alessio Gagliardi and Paolo Lugli},

url = {https://doi.org/10.1038/s41598-018-29882-w},

issn = {2045-2322},

year  = {2018},

date = {2018-01-01},

journal = {Scientific Reports},

volume = {8},

number = {1},

pages = {11386--},

abstract = {In this paper we report for the first time an n-type carbon nanotube field effect transistor which is air- and water-stable, a necessary requirement for electrolyte gated CMOS circuit operation. The device is obtained through a simple process, where the native p-type transistor is converted to an n-type. This conversion is achieved by applying a tailor composed lipophilic membrane containing ion exchanger on the active channel area of the transistor. To demonstrate the use of this transistor in sensing applications, a pH sensor is fabricated. An electrolyte gated CMOS inverter using the herein proposed novel n-type transistor and a classical p-type transistor is demonstrated.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1002/aelm.201800076,

title = {High-Mobility, Solution-Processed Organic Field-Effect Transistors from C8-BTBT:Polystyrene Blends},

author = {Katherina Haase and Cecilia Teixeira da Rocha and Christoph Hauenstein and Yichu Zheng and Mike Hambsch and Stefan C B Mannsfeld},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aelm.201800076},

doi = {10.1002/aelm.201800076},

year  = {2018},

date = {2018-01-01},

journal = {Advanced Electronic Materials},

volume = {4},

number = {8},

pages = {1800076},

abstract = {Abstract Organic field-effect transistors based on aligned small molecule semiconductors have shown high charge carrier mobilities in excess of 10 cm2 V−1 s−1. This makes them a viable alternative to amorphous inorganic semiconductors especially if a high reproducibility can be achieved. Here, the optimization of high mobility organic field-effect transistors based on the organic semiconductor 2,7-dioctyl[1]benzothieno[3,2-b] benzothiophene (C8-BTBT) via the addition of a polymer additive to the printing solution is reported. Specifically, films and devices are compared based on solutions of the neat semiconductor and the blend with polystyrene and shear-coated devices with excellent device characteristics and gate-voltage-independent mobility values reaching 12 cm2 V−1 s−1 are shown, which are the highest reported values for C8-BTBT-based films prepared by a scalable, solution-based process.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{a11040037,

title = {Generalized Kinetic Monte Carlo Framework for Organic Electronics},

author = {Waldemar Kaiser and Johannes Popp and Michael Rinderle and Tim Albes and Alessio Gagliardi},

url = {https://www.mdpi.com/1999-4893/11/4/37},

doi = {10.3390/a11040037},

issn = {1999-4893},

year  = {2018},

date = {2018-01-01},

journal = {Algorithms},

volume = {11},

number = {4},

abstract = {In this paper, we present our generalized kinetic Monte Carlo (kMC) framework for the simulation of organic semiconductors and electronic devices such as solar cells (OSCs) and light-emitting diodes (OLEDs). Our model generalizes the geometrical representation of the multifaceted properties of the organic material by the use of a non-cubic, generalized Voronoi tessellation and a model that connects sites to polymer chains. Herewith, we obtain a realistic model for both amorphous and crystalline domains of small molecules and polymers. Furthermore, we generalize the excitonic processes and include triplet exciton dynamics, which allows an enhanced investigation of OSCs and OLEDs. We outline the developed methods of our generalized kMC framework and give two exemplary studies of electrical and optical properties inside an organic semiconductor.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{KlaukBurghartz2017,

title = {Parameter Uniformity of Submicron-Channel-Length Organic Thin-Film Transistors Fabricated by Stencil Lithography},

author = {U Zschieschang and F Letzkus and J N Burghartz and H Klauk},

doi = {10.1109/TNANO.2017.2655882},

issn = {1536-125X},

year  = {2017},

date = {2017-09-01},

journal = {IEEE Transactions on Nanotechnology},

volume = {16},

number = {5},

pages = {837-841},

abstract = {Using high-resolution stencil lithography, we have fabricated bottom-gate, top-contact (inverted staggered) organic thin-film transistors that have a channel length of 0.5 μm and gate-to-source and gate-to-drain overlaps of 2 μm. Owing to the small channel length, the transistors have a large width-normalized transconductance of (0.50 ± 0.05) S/m, despite the relatively small charge-carrier mobility of (0.36 ± 0.04) cm2/V · s. Across an array of 16 transistors, the uniformity of the transconductance is about 9% (1σ), the uniformity of the carrier mobility is about 7%, the uniformity of the threshold voltage is about 4%, the subthreshold slope varies between 95 and 150 mV/decade, and the on/off current ratio varies between 7 × 104 and 3 × 106. To our knowledge, this is the first time that the parameter distribution of submicron-channel-length organic TFTs is reported.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{7933216,

title = {Flexible Lactate and Glucose Sensors Using Electrolyte-Gated Carbon Nanotube Field Effect Transistor for Non-Invasive Real-Time Monitoring},

author = {S Joshi and V D Bhatt and H Wu and M Becherer and P Lugli},

doi = {10.1109/JSEN.2017.2707521},

issn = {1530-437X},

year  = {2017},

date = {2017-07-01},

journal = {IEEE Sensors Journal},

volume = {17},

number = {14},

pages = {4315-4321},

abstract = {We demonstrate flexible, low cost glucose and lactate sensors 

using novel enzyme immobilization scheme, primarily aimed toward 

wearable devices. The intrinsic chemical nature of polyimide films is 

harnessed to immobilize the enzyme on the polyimide substrate using a 

dicarboxylic acid. Sensors are fabricated using carbon nanotube as an 

active channel material. Minimum degradation of the transistor 

performance is seen after enzyme immobilization. The lowest 

concentration that can be resolved effectively is in pM range. The 

sensors demonstrate good sensing ability in the physiological range for 

wearable and implantable devices. The sensors were re-measured after 

three weeks and still retain their sensing ability with some decrease in 

the sensitivity. They also demonstrate good endurance against mechanical 

deformations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{7843660,

title = {Metal-Free Fully Solution-Processable Flexible Electrolyte-Gated Carbon Nanotube Field Effect Transistor},

author = {V D Bhatt and S Joshi and P Lugli},

doi = {10.1109/TED.2017.2657882},

issn = {0018-9383},

year  = {2017},

date = {2017-03-01},

journal = {IEEE Transactions on Electron Devices},

volume = {64},

number = {3},

pages = {1375-1379},

abstract = {Carbon nanotube-based field effect transistors (CNTFETs) are 

an interesting alternative to organic FETs in the growing field of 

printed electronics. Solution processed CNTFETs can be fabricated at low 

temperatures, are compatible with roll to roll processes and with 

flexible substrates. Usually metal electrodes for CNTFETs are deposited 

using standard techniques (e.g., evaporation or sputtering) which 

require expensive equipment and a high thermal budget. The elimination 

of such deposition step would allow a fully solution-based process for 

the CNTFETs fabrication. In this paper, we demonstrate an all carbon 

nanotube (CNT) transistor which is entirely solution processable without 

sacrificing the device performance. Performed detailed contact 

resistance analysis shows that CNT electrodes make better contacts to 

semiconducting CNTs channel than gold electrodes. The device performance 

is shown for an electrolyte-gated CNTFET fabricated on a flexible 

substrate. Such transistors are used as low cost biosensors for vivo 

implants by exploiting better interaction of flexible substrates to 

cells.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ZSCHIESCHANG2017179,

title = {Below-one-volt organic thin-film transistors with large on/off current ratios},

author = {Ute Zschieschang and Vera Patricia Bader and Hagen Klauk},

url = {http://www.sciencedirect.com/science/article/pii/S1566119917303026},

doi = {https://doi.org/10.1016/j.orgel.2017.06.045},

issn = {1566-1199},

year  = {2017},

date = {2017-01-01},

journal = {Organic Electronics},

volume = {49},

pages = {179 - 186},

abstract = {In many of the applications envisioned for organic thin-film transistors (TFTs), the electrical power will be supplied by small batteries or energy harvesters, which implies that it will be beneficial if the TFTs can be operated with voltages of 1 V or even below 1 V. At the same time, the TFTs should have large on/off current ratios, especially for applications in digital circuits and active matrices. Here we demonstrate p-channel and n-channel organic TFTs fabricated on a flexible plastic substrate that have a turn-on voltage of exactly 0 V, a subthreshold slope of 100 mV/decade, and an on/off current ratio of 2 × 105 when operated with gate-source voltages between 0 and 0.7 V. Complementary inverters fabricated using these TFTs have a small-signal gain of 90 and a minimum noise margin of 79% at a supply voltage of 0.7 V. Complementary ring oscillators can be operated with supply voltages as small as 0.4 V.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Chavarin2017.DOISTART,

title = {Current modulation of a heterojunction structure by an ultra-thin graphene base electrode},

author = {C A Chavarin and C Strobel and J Kitzmann and G Lupina and M Albert and J W Bartha and C Wenger},

year  = {2017},

date = {2017-01-01},

journal = {E-MRS Fall, Warsaw, Symposium S},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{aac317af45c340ff934c0c316df086e4,

title = {First Investigation of N-Doped Amorphous Silicon-Graphene Interfaces for Flexible High Frequency Heterojunction Transistors},

author = {C Strobel and C A Chavarin and J Kitzmann and G Lupina and C Wenger and M Albert and J W Bartha},

year  = {2017},

date = {2017-01-01},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{s17051147,

title = {Flexible, Low-Cost Sensor Based on Electrolyte Gated Carbon Nanotube Field Effect Transistor for Organo-Phosphate Detection},

author = {Vijay Deep Bhatt and Saumya Joshi and Markus Becherer and Paolo Lugli},

url = {http://www.mdpi.com/1424-8220/17/5/1147},

doi = {10.3390/s17051147},

issn = {1424-8220},

year  = {2017},

date = {2017-01-01},

journal = {Sensors},

volume = {17},

number = {5},

abstract = {A flexible enzymatic acetylcholinesterase biosensor based on an electrolyte-gated carbon nanotube field effect transistor is demonstrated. The enzyme immobilization is done on a planar gold gate electrode using 3-mercapto propionic acid as the linker molecule. The sensor showed good sensing capability as a sensor for the neurotransmitter acetylcholine, with a sensitivity of 5.7 μA/decade, and demonstrated excellent specificity when tested against interfering analytes present in the body. As the flexible sensor is supposed to suffer mechanical deformations, the endurance of the sensor was measured by putting it under extensive mechanical stress. The enzymatic activity was inhibited by more than 70% when the phosphate-buffered saline (PBS) buffer was spiked with 5 mg/mL malathion (an organophosphate) solution. The biosensor was successfully challenged with tap water and strawberry juice, demonstrating its usefulness as an analytical tool for organophosphate detection.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Klinger2017,

title = {Organic Power Electronics: Transistor Operation in the kA/cm2 Regime},

author = {Markus P Klinger and Axel Fischer and Felix Kaschura and Johannes Widmer and Bahman Kheradmand-Boroujeni and Frank Ellinger and Karl Leo},

url = {http://dx.doi.org/10.1038/srep44713},

year  = {2017},

date = {2017-01-01},

journal = {Scientific Reports},

volume = {7},

pages = {44713},

publisher = {The Author(s)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{C7NR02793A,

title = {High performance metal-insulator-graphene diodes for radio frequency power detection application},

author = {Mehrdad Shaygan and Zhenxing Wang and Mohamed Saeed Elsayed and Martin Otto and Giuseppe Iannaccone and Ahmed Hamed Ghareeb and Gianluca Fiori and Renato Negra and Daniel Neumaier},

url = {http://dx.doi.org/10.1039/C7NR02793A},

doi = {10.1039/C7NR02793A},

year  = {2017},

date = {2017-01-01},

journal = {Nanoscale},

volume = {9},

pages = {11944-11950},

publisher = {The Royal Society of Chemistry},

abstract = {Vertical metal-insulator-graphene (MIG) diodes for radio frequency (RF) power detection are realized using a scalable approach based on graphene grown by chemical vapor deposition and TiO2 as barrier material. The temperature dependent current flow through the diode can be described by thermionic emission theory taking into account a bias induced barrier lowering at the graphene TiO2 interface. The diodes show excellent figures of merit for static operation, including high on-current density of up to 28 A cm-2, high asymmetry of up to 520, strong maximum nonlinearity of up to 15, and large maximum responsivity of up to 26 V-1, outperforming state-of-the-art metal-insulator-metal and MIG diodes. RF power detection based on MIG diodes is demonstrated, showing a responsivity of 2.8 V W-1 at 2.4 GHz and 1.1 V W-1 at 49.4 GHz.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1063/1.4987147,

title = {Towards high frequency heterojunction transistors: Electrical characterization of N-doped amorphous silicon-graphene diodes},

author = {C Strobel and C A Chavarin and J Kitzmann and G Lupina and Ch. Wenger and M Albert and J W Bartha},

url = {https://doi.org/10.1063/1.4987147},

doi = {10.1063/1.4987147},

year  = {2017},

date = {2017-01-01},

journal = {Journal of Applied Physics},

volume = {121},

number = {24},

pages = {245302},

abstract = {N-type doped amorphous hydrogenated silicon (a-Si:H) is deposited on top of graphene (Gr) by means of very high frequency (VHF) and radio frequency plasma-enhanced chemical vapor deposition (PECVD). In order to preserve the structural integrity of the monolayer graphene, a plasma excitation frequency of 140 MHz was successfully applied during the a-Si:H VHF-deposition. Raman spectroscopy results indicate the absence of a defect peak in the graphene spectrum after the VHF-PECVD of (n)-a-Si:H. The diode junction between (n)-a-Si:H and graphene was characterized using temperature dependent current-voltage (IV) and capacitance-voltage measurements, respectively. We demonstrate that the current at the (n)-a-Si:H-graphene interface is dominated by thermionic emission and recombination in the space charge region. The Schottky barrier height (qΦB), derived by temperature dependent IV-characteristics, is about 0.49 eV. The junction properties strongly depend on the applied deposition method of (n)-a-Si:H with a clear advantage of the VHF(140 MHz)-technology. We have demonstrated that (n)-a-Si:H-graphene junctions are a promising technology approach for high frequency heterojunction transistors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{7604130,

title = {Flexible In-Ga-Zn-O-Based Circuits With Two and Three Metal Layers: Simulation and Fabrication Study},

author = {G Cantarella and K Ishida and L Petti and N M\"{u}nzenrieder and T Meister and R Shabanpour and C Carta and F Ellinger and G Tr\"{o}ster and G A Salvatore},

doi = {10.1109/LED.2016.2619738},

issn = {0741-3106},

year  = {2016},

date = {2016-12-01},

journal = {IEEE Electron Device Letters},

volume = {37},

number = {12},

pages = {1582-1585},

abstract = {The quest for high-performance flexible circuits call for scaling of the minimum feature size in thin-film transistors (TFTs). Although reduced channel lengths can guarantee an improvement in the electrical properties of the devices, proper design rules also play a crucial role to minimize parasitics when designing fast circuits. In this letter, systematic computer-aided design simulations have guided the fabrication of high-performance flexible operational amplifiers (opamps) and logic circuits based on indium-gallium-zinc-oxide TFTs. In particular, the performance improvements due to the use of an additional third metal layer for the interconnections have been estimated for the first time. Encouraged by the simulated enhancements resulting by the decreased parasitic resistances and capacitances, both TFTs and circuits have been realized on a free-standing 50-μm-thick polymide foil using three metal layers. Despite the thicker layer stack, the TFTs have shown mechanical stability down to 5-mm bending radii. Moreover, the opamps and the logic circuits have yielded improved electrical performance with respect to the architecture with two metal layers: gain-bandwidth-product increased by 16.9%, for the first one, and propagation delay (tpd) decreased by 43%, for the latter one.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Chavarin2016.DOISTART,

title = {Structural and electrical characterization of a-Si:H/graphene interfaces grown by VHF PECVD},

author = {C A Chavarin and C Strobel and J Kitzmann and G Lupina and C Wenger and M Albert and J W Bartha},

year  = {2016},

date = {2016-01-01},

journal = {E-MRS Fall, Warsaw, Symposium C},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Grundmann2016a,

title = {Influence of the Cation Ratio on Optical and Electrical Properties of Amorphous Zinc-Tin-Oxide Thin Films Grown by Pulsed Laser Deposition},

author = {Sofie Bitter and Peter Schlupp and Michael Bonholzer and Holger von Wenckstern and Marius Grundmann},

url = {http://dx.doi.org/10.1021/acscombsci.5b00179},

doi = {10.1021/acscombsci.5b00179},

year  = {2016},

date = {2016-01-01},

journal = {ACS Combinatorial Science},

volume = {18},

number = {4},

pages = {188-194},

abstract = {Continuous composition spread (CCS) methods allow fast and economic exploration of composition dependent properties of multielement compounds. Here, a CCS method was applied for room temperature pulsed laser deposition (PLD) of amorphous zinc-tin-oxide to gain detailed insight into the influence of the zinc-to-tin cation ratio on optical and electrical properties of this ternary compound. Our CCS approach for a large-area offset PLD process utilizes a segmented target and thus makes target exchange or movable masks in the PLD chamber obsolete. Cation concentrations of 0.08\textendash0.82 Zn/(Zn + Sn) were achieved across single 50 × 50 mm2 glass substrates. The electrical conductivity increases for increasing tin content, and the absorption edge shifts to lower energies. The free carrier concentration can be tuned from 1020 to 1016 cm\textendash3 by variation of the cation ratio from 0.1 to 0.5 Zn/(Zn + Sn).},

note = {PMID: 27004935},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Grundmann2016b,

title = {Oxide bipolar electronics: materials, devices and circuits},

author = {Marius Grundmann and Fabian Kl\"{u}pfel and Robert Karsthof and Peter Schlupp and Friedrich-Leonhard Schein and Daniel Splith and Chang Yang and Sofie Bitter and Holger von Wenckstern},

url = {http://stacks.iop.org/0022-3727/49/i=21/a=213001},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Physics D: Applied Physics},

volume = {49},

number = {21},

pages = {213001},

publisher = {IOP Publishing},

abstract = {We present the history of, and the latest progress in, the field of bipolar oxide thin film devices. As such we consider primarily pn-junctions in which at least one of the materials is a metal oxide semiconductor. A wide range of n-type and p-type oxides has been explored for the formation of such bipolar diodes. Since most oxide semiconductors are unipolar, challenges and opportunities exist with regard to the formation of heterojunction diodes and band lineups. Recently, various approaches have led to devices with high rectification, namely p-type ZnCo 2 O 4 and NiO on n-type ZnO and amorphous zinc-tin-oxide. Subsequent bipolar devices and applications such as photodetectors, solar cells, junction field-effect transistors and integrated circuits like inverters and ring oscillators are discussed. The tremendous progress shows that bipolar oxide electronics has evolved from the exploration of various materials and heterostructures to the demonstration of functioning integrated circuits. Therefore a viable, facile and high performance technology is ready for further exploitation and performance optimization.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Grundmann2016bb,

title = {Ring Oscillators Based on ZnO Channel JFETs and MESFETs},

author = {Fabian J Kl\"{u}pfel and Holger von Wenckstern and Marius Grundmann},

url = {http://dx.doi.org/10.1002/aelm.201500431},

doi = {10.1002/aelm.201500431},

issn = {2199-160X},

year  = {2016},

date = {2016-01-01},

journal = {Advanced Electronic Materials},

volume = {2},

number = {7},

pages = {1500431--n/a},

publisher = {Wiley Online Library},

abstract = {Ring oscillator circuits based on junction field-effect transistors as well as metal\textendashsemiconductor field-effect transistors with ZnO channels are presented. Single stage delay times down to 110 ns are observed. The experimental oscillation frequencies are related to easily measurable device properties by a simple analytical model. This work proves the feasibility of low power oxide based circuits with Schottky diode and bipolar (pn-) diode gates since both approaches provide significantly lower operation voltages at similar frequencies compared to previously reported oxide thin film transistors based on insulating gates.},

note = {1500431},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{BarthaWenger2016,

title = {Plasma-enhanced chemical vapor deposition of amorphous Si on graphene},

author = {G Lupina and C Strobel and J Dabrowski and G Lippert and J Kitzmann and H M Krause and C Wenger and M Lukosius and A Wolff and M Albert and J W Bartha},

url = {http://dx.doi.org/10.1063/1.4948978},

doi = {10.1063/1.4948978},

year  = {2016},

date = {2016-01-01},

journal = {Applied Physics Letters},

volume = {108},

number = {19},

pages = {193105},

publisher = {AIP Publishing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1063/1.4953034,

title = {Metal oxide semiconductor thin-film transistors for flexible electronics},

author = {Luisa Petti and Niko M\"{u}nzenrieder and Christian Vogt and Hendrik Faber and Lars B\"{u}the and Giuseppe Cantarella and Francesca Bottacchi and Thomas D Anthopoulos and Gerhard Tr\"{o}ster},

url = {https://doi.org/10.1063/1.4953034},

doi = {10.1063/1.4953034},

year  = {2016},

date = {2016-01-01},

journal = {Applied Physics Reviews},

volume = {3},

number = {2},

pages = {021303},

abstract = {The field of flexible electronics has rapidly expanded over the last decades, pioneering novel applications, such as wearable and textile integrated devices, seamless and embedded patch-like systems, soft electronic skins, as well as imperceptible and transient implants. The possibility to revolutionize our daily life with such disruptive appliances has fueled the quest for electronic devices which yield good electrical and mechanical performance and are at the same time light-weight, transparent, conformable, stretchable, and even biodegradable. Flexible metal oxide semiconductor thin-film transistors (TFTs) can fulfill all these requirements and are therefore considered the most promising technology for tomorrow's electronics. This review reflects the establishment of flexible metal oxide semiconductor TFTs, from the development of single devices, large-area circuits, up to entirely integrated systems. First, an introduction on metal oxide semiconductor TFTs is given, where the history of the field is revisited, the TFT configurations and operating principles are presented, and the main issues and technological challenges faced in the area are analyzed. Then, the recent advances achieved for flexible n-type metal oxide semiconductor TFTs manufactured by physical vapor deposition methods and solution-processing techniques are summarized. In particular, the ability of flexible metal oxide semiconductor TFTs to combine low temperature fabrication, high carrier mobility, large frequency operation, extreme mechanical bendability, together with transparency, conformability, stretchability, and water dissolubility is shown. Afterward, a detailed analysis of the most promising metal oxide semiconducting materials developed to realize the state-of-the-art flexible p-type TFTs is given. Next, the recent progresses obtained for flexible metal oxide semiconductor-based electronic circuits, realized with both unipolar and complementary technology, are reported. In particular, the realization of large-area digital circuitry like flexible near field communication tags and analog integrated circuits such as bendable operational amplifiers is presented. The last topic of this review is devoted for emerging flexible electronic systems, from foldable displays, power transmission elements to integrated systems for large-area sensing and data storage and transmission. Finally, the conclusions are drawn and an outlook over the field with a prediction for the future is provided.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Neumaier2016a,

title = {Encapsulated graphene-based Hall sensors on foil with increased sensitivity},

author = {Zhenxing Wang and Luca Banszerus and Martin Otto and Kenji Watanabe and Takashi Taniguchi and Christoph Stampfer and Daniel Neumaier},

url = {http://dx.doi.org/10.1002/pssb.201600224},

doi = {10.1002/pssb.201600224},

issn = {1521-3951},

year  = {2016},

date = {2016-01-01},

journal = {physica status solidi (b)},

volume = {253},

number = {12},

pages = {2316--2320},

publisher = {Wiley Online Library},

abstract = {The encapsulation of graphene-based Hall sensors on foil is shown to be an effective method for improving the performance in terms of higher sensitivity for magnetic field detection. Two types of encapsulation were investigated: a simple encapsulation of graphene with polymethyl methacrylate (PMMA) as a proof of concept and an encapsulation with mechanically exfoliated hexagonal boron nitride (hBN). The Hall sensor with PMMA encapsulation already shows higher sensitivity compared to the one without encapsulation. However, the Hall sensor with graphene encapsulated between two stacks of hBN shows a current and a voltage normalized sensitivity of up to 2270 V/AT and 0.68 V/VT, respectively, which are the highest reported sensitivity values for Hall sensors on foil so far.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Neumaier2016b,

title = {Flexible Hall sensors based on graphene},

author = {Zhenxing Wang and Mehrdad Shaygan and Martin Otto and Daniel Schall and Daniel Neumaier},

url = {http://dx.doi.org/10.1039/C5NR08729E},

doi = {10.1039/C5NR08729E},

year  = {2016},

date = {2016-01-01},

journal = {Nanoscale},

volume = {8},

pages = {7683-7687},

publisher = {The Royal Society of Chemistry},

abstract = {The excellent electronic and mechanical properties of graphene provide a perfect basis for high performance flexible electronic and sensor devices. Here, we present the fabrication and characterization of flexible graphene based Hall sensors. The Hall sensors are fabricated on 50 [small mu ]m thick flexible Kapton foil using large scale graphene grown by chemical vapor deposition technique on copper foil. Voltage and current normalized sensitivities of up to 0.096 V VT-1 and 79 V AT-1 were measured, respectively. These values are comparable to the sensitivity of rigid silicon based Hall sensors and are the highest values reported so far for any flexible Hall sensor devices. The sensitivity of the Hall sensor shows no degradation after being bent to a minimum radius of 4 mm, which corresponds to a tensile strain of 0.6%, and after 1000 bending cycles to a radius of 5 mm.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}