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Hideo Hosono - One of the best experts on this subject based on the ideXlab platform.
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material design of p type transparent Amorphous Semiconductor cu sn i
Advanced Materials, 2018Co-Authors: Masato Sasase, Hideo HosonoAbstract:: Transparent Amorphous Semiconductors (TAS) that can be fabricated at low temperature are key materials in the practical application of transparent flexible electronics. Although various n-type TAS materials with excellent performance, such as Amorphous In-Ga-Zn-O (a-IGZO), are already known, no complementary p-type TAS has been realized to date. Here, a material design concept for p-type TAS materials is proposed utilizing the pseudo s-orbital nature of spatially spreading iodine 5p orbitals and Amorphous Sn-containing CuI (a-CuSnI) thin film is reported as an example. The resulting a-CuSnI thin films fabricated by spin coating at low temperature (140 °C) have a smooth surface. The Hall mobility increases with the hole concentration and the largest mobility of ≈9 cm2 V-1 s-1 is obtained, which is comparable with that of conventional n-type TAS.
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origins of high mobility and low operation voltage of Amorphous oxide tfts electronic structure electron transport defects and doping
IEEE\ OSA Journal of Display Technology, 2009Co-Authors: Toshio Kamiya, Kenji Nomura, Hideo HosonoAbstract:Amorphous oxide Semiconductors (AOSs) are expected as new channel materials in thin-film transistors (TFTs) for large-area and/or flexible flat-panel displays and other giant-microelectronics devices. So far, many prototype displays have been demonstrated in these four years since the first report of AOS TFT. The most prominent feature of AOS TFTs is that they operate with good performances even if they are fabricated at low temperatures without a defect passivation treatment. The TFT mobilities exceed 10 cm2/(Vmiddots), which are more than ten times larger than those of conventional Amorphous Semiconductor devices. In addition, they operate at low voltages, e.g., < 5 V owing to their small subthreshold voltage swings. These features indicate that electron transport in oxide Semiconductors are insensitive to random structures and these oxides do not form high-density defects that affect electron transport and TFT operation. In this paper, we discuss the origins of the prominent features of AOS devices from the viewpoint of materials science of AOS.
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novel oxide Amorphous Semiconductors transparent conducting Amorphous oxides
Journal of Non-crystalline Solids, 1996Co-Authors: Hideo Hosono, Masahiro Yasukawa, Hiroshi KawazoeAbstract:A working hypothesis to find wide gap oxide Semiconductors was proposed on the basis of simple considerations. The hypothesis predicts that Amorphous double oxides composed of heavy metal cations (HMCs) with an electronic configuration (n − 1)d10s0 are promising candidates for a novel class of Amorphous Semiconductors. Electrical and optical properties of three Amorphous double oxides composed of the HMCs, a-AgSbO3, Cd2GeO4 and Cd2PbO4, were examined, following this hypothesis. It was found that when carrier electrons are generated via the formation of oxygen vacancies or doping of excess cations by ion implantation, these three wide band gap Amorphous oxides show high electrical conductivities of 10−1 to 102 S cm−1 at ∼ 300 K and the conductivity remains almost constant down to 77 or 4 K for high carrier concentrations (> 1018 cm−3). This high conductivity originates primarily from a large Hall mobility of ∼ 10 cm2 V−1 s−1, which is higher by several orders of magnitude than that in Amorphous transition metal oxides, Si:H and chalcogenides. A variety of chemical compositions for a novel oxide Amorphous Semiconductor are suggested.
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new Amorphous Semiconductor 2cdo pbox
Applied Physics Letters, 1996Co-Authors: Hideo Hosono, Hiroshi Kawazoe, Yasuhisa Yamashita, Naoyuki Ueda, Kenichi ShimidzuAbstract:A new Amorphous Semiconductor, 2CdO⋅PbOx (band gap: 1.58 eV), was found. Thin films of this material were prepared by rf sputtering of a Cd2PbO4 target in O2–Ar. The dc conductivity of the resulting Amorphous thin films was ∼180 S cm−1 at 300 K and remained almost constant down to ∼4 K. The concentration of carrier electrons and the Hall mobility in the as‐deposited state were 1×1020 cm−3 and 9 cm2 V−1 s−1, respectively. When the as‐deposited specimens were heated to 250 °C, which is far below the crystallization (to Cd2PbO4) temperature (460 °C), the conductivity and the carrier concentration at 300 K became approximately twice as high. The thermal O2‐desorption measurements demonstrated that carrier electrons are generated via the formation of oxygen vacancies at the initial stage (<250 °C) of thermal desorption of O2 from the Amorphous structure. The effective mass of carrier electrons was estimated as 0.57m0.
Arokia Nathan - One of the best experts on this subject based on the ideXlab platform.
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unified analytic model for current voltage behavior in Amorphous oxide Semiconductor tfts
IEEE Electron Device Letters, 2014Co-Authors: Sungsik Lee, D Striakhilev, Sanghun Jeon, Arokia NathanAbstract:We present a simple and semi-physical analytical description of the current-voltage characteristics of Amorphous oxide Semiconductor thin-film transistors in the above-threshold and sub-threshold regions. Both regions are described by single unified expression that employs the same set of model parameter values directly extracted from measured terminal characteristics. The model accurately reproduces measured characteristics of Amorphous Semiconductor thin film transistors in general, yielding a scatter of <;4%.
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modeling sub threshold current voltage characteristics in thin film transistors
IEEE\ OSA Journal of Display Technology, 2013Co-Authors: Sungsik Lee, Sanghun Jeon, Arokia NathanAbstract:In this paper, we present a physically-based compact model for the sub-threshold behavior in a TFT with an Amorphous Semiconductor channel. Both drift and diffusion current components are considered and combined using an harmonic average. Here, the diffusion component describes the exponential current behavior due to interfacial deep states, while the drift component is associated with presence of localized deep states formed by dangling bonds broken from weak bonds in the bulk and follows a power law. The proposed model yields good agreement with measured results.
Sungjin Choi - One of the best experts on this subject based on the ideXlab platform.
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fully current based sub bandgap optoelectronic differential ideality factor technique and extraction of subgap dos in Amorphous Semiconductor tfts
IEEE Transactions on Electron Devices, 2014Co-Authors: Hyunjun Choi, Junseok Hwang, Saeroonter Oh, Sungjin ChoiAbstract:A sub-bandgap optoelectronic differential ideality factor technique is proposed for extraction of the intrinsic density-of-states (DOS) over the bandgap in Amorphous Semiconductor thin-film transistors (TFTs). In the proposed technique, the gate bias-dependent differential change in the difference of ideality factors (dAη(V GS )/dV GS ) between dark and sub-bandgap photonic excitation condition is employed. With the sub-bandgap photons (hν <; E g ), the photonic excitation of electrons is confined only from the localized DOS over the bandgap. We applied the proposed technique to a-InGaZnO TFTs with W/L = 50/25 μm/μm and extracted the energy distribution of the intrinsic DOS for the localized states over the bandgap.
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single scan monochromatic photonic capacitance voltage technique for extraction of subgap dos over the bandgap in Amorphous Semiconductor tfts
IEEE Electron Device Letters, 2013Co-Authors: Hagyoul Bae, Hyunjun Choi, Junseok Hwang, Sungjin Choi, Sungwoo Jun, Yun Hyeok Kim, Jaeyeop Ahn, Jonguk Bae, Dae Hwan Kim, Dong Myong KimAbstract:We report a novel technique for simultaneous extraction of subgap donor- and acceptor-like density of states [gD(E) and gA(E)] over the subgap energy range (EV <;E<;EC) using a single-scan monochromatic photonic capacitance-voltage technique in n-channel Amorphous indium-gallium-zinc-oxide thin-film transistors. In the proposed technique, we applied two different equivalent circuit models for the photoresponsive carriers excited from gD(E) and gA(E) under depletion (VGS <; VFB) and accumulation (VGS <; VFB) bias by employing a sub-bandgap optical source that includes a relation between photon energy (Eph) and bandgap energy (Eg) as hv = Eph <; Eg.
Dong Myong Kim - One of the best experts on this subject based on the ideXlab platform.
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single scan monochromatic photonic capacitance voltage technique for extraction of subgap dos over the bandgap in Amorphous Semiconductor tfts
IEEE Electron Device Letters, 2013Co-Authors: Hagyoul Bae, Hyunjun Choi, Junseok Hwang, Sungjin Choi, Sungwoo Jun, Yun Hyeok Kim, Jaeyeop Ahn, Jonguk Bae, Dae Hwan Kim, Dong Myong KimAbstract:We report a novel technique for simultaneous extraction of subgap donor- and acceptor-like density of states [gD(E) and gA(E)] over the subgap energy range (EV <;E<;EC) using a single-scan monochromatic photonic capacitance-voltage technique in n-channel Amorphous indium-gallium-zinc-oxide thin-film transistors. In the proposed technique, we applied two different equivalent circuit models for the photoresponsive carriers excited from gD(E) and gA(E) under depletion (VGS <; VFB) and accumulation (VGS <; VFB) bias by employing a sub-bandgap optical source that includes a relation between photon energy (Eph) and bandgap energy (Eg) as hv = Eph <; Eg.
Hyunjun Choi - One of the best experts on this subject based on the ideXlab platform.
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fully current based sub bandgap optoelectronic differential ideality factor technique and extraction of subgap dos in Amorphous Semiconductor tfts
IEEE Transactions on Electron Devices, 2014Co-Authors: Hyunjun Choi, Junseok Hwang, Saeroonter Oh, Sungjin ChoiAbstract:A sub-bandgap optoelectronic differential ideality factor technique is proposed for extraction of the intrinsic density-of-states (DOS) over the bandgap in Amorphous Semiconductor thin-film transistors (TFTs). In the proposed technique, the gate bias-dependent differential change in the difference of ideality factors (dAη(V GS )/dV GS ) between dark and sub-bandgap photonic excitation condition is employed. With the sub-bandgap photons (hν <; E g ), the photonic excitation of electrons is confined only from the localized DOS over the bandgap. We applied the proposed technique to a-InGaZnO TFTs with W/L = 50/25 μm/μm and extracted the energy distribution of the intrinsic DOS for the localized states over the bandgap.
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single scan monochromatic photonic capacitance voltage technique for extraction of subgap dos over the bandgap in Amorphous Semiconductor tfts
IEEE Electron Device Letters, 2013Co-Authors: Hagyoul Bae, Hyunjun Choi, Junseok Hwang, Sungjin Choi, Sungwoo Jun, Yun Hyeok Kim, Jaeyeop Ahn, Jonguk Bae, Dae Hwan Kim, Dong Myong KimAbstract:We report a novel technique for simultaneous extraction of subgap donor- and acceptor-like density of states [gD(E) and gA(E)] over the subgap energy range (EV <;E<;EC) using a single-scan monochromatic photonic capacitance-voltage technique in n-channel Amorphous indium-gallium-zinc-oxide thin-film transistors. In the proposed technique, we applied two different equivalent circuit models for the photoresponsive carriers excited from gD(E) and gA(E) under depletion (VGS <; VFB) and accumulation (VGS <; VFB) bias by employing a sub-bandgap optical source that includes a relation between photon energy (Eph) and bandgap energy (Eg) as hv = Eph <; Eg.