TY - JOUR
T1 - Polycrystalline In-Ga-O Thin-Film Transistors Coupled with a Nitrogen Doping Technique for High-Performance UV Detectors
AU - Cheng, Yen Chi
AU - Chang, Sheng Po
AU - Chen, Ih Chin
AU - Tsai, Yen Lin
AU - Cheng, Tien Hung
AU - Chang, Shoou Jinn
N1 - Funding Information:
Manuscript received August 16, 2019; revised October 3, 2019 and October 30, 2019; accepted November 13, 2019. Date of publication December 16, 2019; date of current version December 30, 2019. This work was supported in part by the Ministry of Science and Technology under Contract MOST 106-2221-E-006-178 and Contract MOST 107-2221-E-006-146, in part by the Center for Frontier Materials and Micro/Nano Science and Technology, National Cheng Kung University, Taiwan, and in part by the Advanced Optoelectronic Technology Center, National Cheng Kung University, for projects from the Ministry of Education. The review of this article was arranged by Editor J. Huang. (Corresponding author: Sheng-Po Chang.) The authors are with the Institute of Microelectronics and Department of Electrical Engineering, Advanced Optoelectronic Technology Center, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan (e-mail: [email protected]).
Publisher Copyright:
© 1963-2012 IEEE.
PY - 2020/1
Y1 - 2020/1
N2 - In this article, thin-film transistors (TFTs) with a polycrystalline indium-gallium-oxide (poly IGO) active layer were fabricated for ultraviolet (UV) detection. To achieve better sensing performance, an in situ nitrogen doping (N-doping) technique was employed to passivate the excessive defect states in the bandgap. Under UV illumination, it is evident that the N-doped IGO TFT exhibited superior photoresponsivity and UV-to-visible rejection ratio (17.4 A/W and 1.0 × 106) as compared to the undoped one (13.1 A/W and 1.2 × 105). More importantly, a sharper responsivity cutoff at 340 nm (Eg∼ 3.65 eV) was observed, suggesting that the N-doped phototransistor had better wavelength selectivity. Through X-ray photoelectron spectroscopy analysis, it was shown that N-doping reduced the subgap states and thus suppressed the visible light-induced ionization of oxygen vacancy. Furthermore, the nitrogen incorporation slightly reduced the effective bandgap, which enhanced the band-to-band electron transition and the UV responsivity.
AB - In this article, thin-film transistors (TFTs) with a polycrystalline indium-gallium-oxide (poly IGO) active layer were fabricated for ultraviolet (UV) detection. To achieve better sensing performance, an in situ nitrogen doping (N-doping) technique was employed to passivate the excessive defect states in the bandgap. Under UV illumination, it is evident that the N-doped IGO TFT exhibited superior photoresponsivity and UV-to-visible rejection ratio (17.4 A/W and 1.0 × 106) as compared to the undoped one (13.1 A/W and 1.2 × 105). More importantly, a sharper responsivity cutoff at 340 nm (Eg∼ 3.65 eV) was observed, suggesting that the N-doped phototransistor had better wavelength selectivity. Through X-ray photoelectron spectroscopy analysis, it was shown that N-doping reduced the subgap states and thus suppressed the visible light-induced ionization of oxygen vacancy. Furthermore, the nitrogen incorporation slightly reduced the effective bandgap, which enhanced the band-to-band electron transition and the UV responsivity.
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U2 - 10.1109/TED.2019.2955758
DO - 10.1109/TED.2019.2955758
M3 - Article
AN - SCOPUS:85077809191
SN - 0018-9383
VL - 67
SP - 140
EP - 145
JO - IEEE Transactions on Electron Devices
JF - IEEE Transactions on Electron Devices
IS - 1
M1 - 8933340
ER -