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Title: Solution-processed PCDTBT capped low-voltage InGaZnO{sub x} thin film phototransistors for visible-light detection

The effects of visible-light detection based on solution processed poly[N-9′′-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′, 3′benzothiadiazole) (PCDTBT) capped InGaZnOx (IGZO) phototransistors with Al{sub 2}O{sub x} serving as gate dielectric are investigated in this paper. The high-k dielectric is used to lower the device operating voltage down to 2 V. Photons emitted from laser sources with the wavelengths (λ) of 532 nm and 635 nm are absorbed through the layer of PCDTBT to generate electron-hole-pairs (EHPs). After the separation of EHPs, electrons are injected into IGZO layer through the p-n junction formed between the IGZO (n-type semiconductor) and the PCDTBT (p-type semiconductor). The photo-generated carriers boost the drain current of the transistors as well as bring about the negative threshold voltage shift. Significant enhanced detection performance is achieved under the laser wavelength of 532 nm. The highest photoresponsivity reaches up to 20 A/W, while the photoresponse rise time comes to 10 ms and the fall time comes to approximate 76 ms, which is much faster than trap assisted IGZO visible light detection. The fabricated phototransistors favor the application of visible-light detectors and/or optical switches.
Authors:
; ; ; ; ;  [1]
  1. Department of Electronic Engineering and Materials Science and Technology Research Center, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China)
Publication Date:
OSTI Identifier:
22483068
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 24; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARRIERS; DETECTION; DIELECTRIC MATERIALS; ELECTRIC POTENTIAL; EMISSION; LASERS; LAYERS; MATHEMATICAL SOLUTIONS; PHOTOTRANSISTORS; P-N JUNCTIONS; PULSE RISE TIME; SEMICONDUCTOR MATERIALS; THIN FILMS; TRAPS; WAVELENGTHS