Author
David J. Gundlach
Other affiliations: Pennsylvania State University, ETH Zurich, Rolf C. Hagen Group
Bio: David J. Gundlach is an academic researcher from National Institute of Standards and Technology. The author has contributed to research in topics: Thin-film transistor & Organic semiconductor. The author has an hindex of 55, co-authored 146 publications receiving 13970 citations. Previous affiliations of David J. Gundlach include Pennsylvania State University & ETH Zurich.
Papers published on a yearly basis
Papers
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TL;DR: In this article, photolithographically defined organic thin-film transistors (OTFTs) with improved field-effect mobility and sub-threshold slope were fabricated using two layers of pentacene deposited at different substrate temperatures.
Abstract: Using two layers of pentacene deposited at different substrate temperatures as the active material, we have fabricated photolithographically defined organic thin-film transistors (OTFTs) with improved field-effect mobility and subthreshold slope. These devices use photolithographically defined gold source and drain electrodes and octadecyltrichlorosilane-treated silicon dioxide gate dielectric. The devices have field-effect mobility as large as 1.5 cm/sup 2//V-s, on/off current ratio larger than 10/sup 8/, near zero threshold voltage, and subthreshold slope less than 1.6 V per decade. To our knowledge, this is the largest field-effect mobility and smallest subthreshold slope yet reported for any organic transistor, and the first time both of these important characteristics have been obtained for a single device.
915 citations
TL;DR: In this article, the authors have fabricated organic thin-film transistor (OTFT)-driven active matrix liquid crystal displays on flexible polymeric substrates using a low-temperature process.
Abstract: We have fabricated organic thin-film transistor (OTFT)-driven active matrix liquid crystal displays on flexible polymeric substrates. These small displays have 16×16 pixel polymer-dispersed liquid crystal arrays addressed by pentacene active layer OTFTs. The displays were fabricated using a low-temperature process (<110 °C) on flexible polyethylene naphthalate film and are operated as reflective active matrix displays.
792 citations
TL;DR: In this article, the authors explored the charge-carrier transport mechanism in the organic semiconductor pentacene using thin-film transistor structures and found that the variation of the field-effect mobility with temperature differs from sample to sample, ranging from thermally activated to temperature-independent behavior.
Abstract: The charge-carrier transport mechanism in the organic semiconductor pentacene is explored using thin-film transistor structures. The variation of the field-effect mobility with temperature differs from sample to sample, ranging from thermally activated to temperature-independent behavior. This result excludes thermally activated hopping as the fundamental transport mechanism in pentacene thin films, and suggests that traps and/or contact effects may strongly influence the observed characteristics. These results also indicate that field-effect transistors may not be appropriate vehicles for illuminating basic transport mechanisms in organic materials.
768 citations
TL;DR: Pentacene-based organic thin-film transistors (TFT's) with field effect mobility as large as 0.7 cm/sup 2/V/spl middot/s and on/off current ratio larger than 10/sup 8/ have been fabricated as mentioned in this paper.
Abstract: Pentacene-based organic thin-film transistors (TFT's) with field-effect mobility as large as 0.7 cm/sup 2//V/spl middot/s and on/off current ratio larger than 10/sup 8/ have been fabricated. Pentacene films deposited by evaporation at elevated temperature at low-to-moderate deposition rates have a high degree of molecular ordering with micrometer-sized and larger dendritic grains. Such films yield TFT's with large mobility. Films deposited at low temperature or by flash evaporation have small grains and poor molecular ordering and yield TFT's with low mobility.
754 citations
TL;DR: In this paper, the authors demonstrate controllable shift of the threshold voltage and the turn-on voltage in pentacene thin film transistors and rubrene single crystal field effect transistors by the use of nine organosilanes with different functional groups.
Abstract: We demonstrate controllable shift of the threshold voltage and the turn-on voltage in pentacene thin film transistors and rubrene single crystal field effect transistors (FET) by the use of nine organosilanes with different functional groups. Prior to depositing the organic semiconductors, the organosilanes were applied to the SiO2 gate insulator from solution and form a self-assembled monolayer (SAM). The observed shifts of the transfer characteristics range from −2to50V and can be related to the surface potential of the layer next to the transistor channel. Concomitantly the mobile charge carrier concentration at zero gate bias reaches up to 4×1012∕cm2. In the single crystal FETs the measured transfer characteristics are also shifted, while essentially maintaining the high quality of the subthreshold swing. The shift of the transfer characteristics is governed by the built-in electric field of the SAM and can be explained using a simple energy level diagram. In the thin film devices, the subthreshold re...
532 citations
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TL;DR: Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability as discussed by the authors, and its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability.
Abstract: The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light-emitting devices to touch screens, photodetectors and ultrafast lasers. Here we review the state-of-the-art in this emerging field.
6,863 citations
TL;DR: The future holds even greater promise for this technology, with an entirely new generation of ultralow-cost, lightweight and even flexible electronic devices in the offing, which will perform functions traditionally accomplished using much more expensive components based on conventional semiconductor materials such as silicon.
Abstract: Organic electronics are beginning to make significant inroads into the commercial world, and if the field continues to progress at its current, rapid pace, electronics based on organic thin-film materials will soon become a mainstay of our technological existence. Already products based on active thin-film organic devices are in the market place, most notably the displays of several mobile electronic appliances. Yet the future holds even greater promise for this technology, with an entirely new generation of ultralow-cost, lightweight and even flexible electronic devices in the offing, which will perform functions traditionally accomplished using much more expensive components based on conventional semiconductor materials such as silicon.
4,967 citations
IBM1
TL;DR: In this article, the authors present new insight into conduction mechanisms and performance characteristics, as well as opportunities for modeling properties of organic thin-film transistors (OTFTs) and discuss progress in the growing field of n-type OTFTs.
Abstract: Organic thin-film transistors (OTFTs) have lived to see great improvements in recent years. This review presents new insight into conduction mechanisms and performance characteristics, as well as opportunities for modeling properties of OTFTs. The shifted focus in research from novel chemical structures to fabrication technologies that optimize morphology and structural order is underscored by chapters on vacuum-deposited and solution-processed organic semiconducting films. Finally, progress in the growing field of the n-type OTFTs is discussed in ample detail. The Figure, showing a pentacene film edge on SiO2, illustrates the morphology issue.
4,804 citations
TL;DR: An antisolvent vapor-assisted crystallization approach is reported that enables us to create sizable crack-free MAPbX3 single crystals with volumes exceeding 100 cubic millimeters, which enabled a detailed characterization of their optical and charge transport characteristics.
Abstract: The fundamental properties and ultimate performance limits of organolead trihalide MAPbX3 (MA = CH3NH3(+); X = Br(-) or I(-)) perovskites remain obscured by extensive disorder in polycrystalline MAPbX3 films. We report an antisolvent vapor-assisted crystallization approach that enables us to create sizable crack-free MAPbX3 single crystals with volumes exceeding 100 cubic millimeters. These large single crystals enabled a detailed characterization of their optical and charge transport characteristics. We observed exceptionally low trap-state densities on the order of 10(9) to 10(10) per cubic centimeter in MAPbX3 single crystals (comparable to the best photovoltaic-quality silicon) and charge carrier diffusion lengths exceeding 10 micrometers. These results were validated with density functional theory calculations.
3,939 citations
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TL;DR: In this article, a review summarizes recent progress in the development of polymer solar cells and provides a synopsis of major achievements in the field over the past few years, while potential future developments and the applications of this technology are also briefly discussed.
Abstract: This Review summarizes recent progress in the development of polymer solar cells. It covers the scientific origins and basic properties of polymer solar cell technology, material requirements and device operation mechanisms, while also providing a synopsis of major achievements in the field over the past few years. Potential future developments and the applications of this technology are also briefly discussed.
3,832 citations