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Title: Anomalous high photoconductivity in short channel indium-zinc-oxide photo-transistors

Upon light exposure, an indium-zinc-oxide (IZO) thin-film transistor (TFT) presents higher photoconductivity by several orders of magnitude at the negative gate bias region. Among various device geometrical factors, scaling down the channel length of the photo-transistor results in an anomalous increase in photoconductivity. To probe the origin of this high photoconductivity in short-channel device, we measured transient current, current–voltage, and capacitance–voltage characteristics of IZO–TFTs with various channel lengths and widths before and after illumination. Under the illumination, the equilibrium potential region which lies far from front interface exists only in short-channel devices, forming the un-depleted conducting back channel. This region plays an important role in carrier transport under the illumination, leading to high photoconductivity in short-channel devices. Photon exposure coupled with gate-modulated band bending for short-channel devices leads to the accumulation of V{sub o}{sup ++} at the front channel and screening negative gate bias, thereby generating high current flow in the un-depleted back-channel region.
Authors:
 [1] ;  [2]
  1. Semiconductor Device Laboratory, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Corporation, Gyeonggi 449-712 (Korea, Republic of)
  2. Department of Applied Physics and Department of Display and Semiconductor Physics, Korea University, 2511 Sejongro, Sejong, 339-700 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22395677
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CAPACITANCE; CHARGE CARRIERS; ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; EQUILIBRIUM; ILLUMINANCE; INTERFACES; OXYGEN IONS; PHOTOCONDUCTIVITY; PHOTONS; THIN FILMS; TRANSIENTS; TRANSISTORS; VISIBLE RADIATION; ZINC OXIDES