Fast-speed self-powered PEDOT:PSS/α-Ga₂O₃ nanorod array/FTO photodetector with solar-blind UV/visible dual-band photodetection

Abstract

The α-Ga2O3 nanorod array is grown on FTO by hydrothermal and annealing processes. And a self-powered PEDOT:PSS/α-Ga2O3 nanorod array/FTO (PGF) photodetector has been demonstrated by spin coating PEDOT:PSS on the α-Ga2O3 nanorod array. Successfully, the PGF photodetector shows solar-blind UV/visible dual-band photodetection. Our device possesses comparable solar-blind UV responsivity (0.18 mA/W at 235 nm) and much faster response speed (0.102 s) than most of the reported self-powered α-Ga2O3 nanorod array solar-blind UV photodetectors. And it presents the featured and distinguished visible band photoresponse with a response speed of 0.136 s at 540 nm. The response time is also much faster than the other non-self-powered β-Ga2O3 DUV/visible dual-band photodetectors due to the fast-speed separation of photogenerated carries by the built-in electric field in the depletion regions of PEDOT:PSS/α-Ga2O3 heterojunction. The results herein may prove a promising way to realize fast-speed self-powered α-Ga2O3 photodetectors with solar-blind UV/visible dual-band photodetection by simple processes for the applications of multiple-target tracking, imaging, machine vision and communication.

Fabrication of Al doped α-GaOOH nanorod arrays on FTO for self-powered photoelectrochemical solar-blind UV photodetectors

“…In spite of the fixed Ga/Al ratio of 1:1 in the precursor concentrations, Al content from EDS decreases with increasing Ga precursor concentrations. It is noteworthy that increasing the concentrations of gallium nitrate aqueous solutions can results in larger thickness of α-GaOOH nanorod arrays on FTO [18,19]. Therefore, Al concentrations in Al doped α-GaOOH nanorods may be relevant with the length of nanorod arrays.…”

Photoelectrochemical properties of self-powered corundum-structured Ga2O3 nanorod array/fluorine-doped SnO2 photodetectors modulated by precursor concentrations

“…Among polymorphs of Ga 2 O 3 , corundum-structured Ga 2 O 3 (α-Ga 2 O 3 ) and monoclinic Ga 2 O 3 (β-Ga 2 O 3 ) are usually utilized as photosensitive materials [1,2,. However, in comparison to the most stable β-Ga 2 O 3 , metastable-phase α-Ga 2 O 3 has lower fabrication temperature [1,2,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Therefore, α-Ga 2 O 3 based solar-blind UV photodetectors have been paid more attention in recent studies [2,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

Solution-Processed Ga2O3 Films via Thermal Annealing for Solar Blind Ultraviolet Photovoltaic Photodetectors with High Photoresponsivity and Fast Response

“…Gallium oxide (Ga 2 O 3 ), a 4.9–5.2 eV wide-band-gap semiconductor with large near band edge absorption coefficient, high thermodynamic stability, and great chemical stability, is considered to be one of the mainstream materials for fabricating SBUV detectors. – Recently, a variety of methods used to grow Ga 2 O 3 materials have been developed, such as MOCVD, PLD, and magnetron sputtering. – However, these methods require strict processes and costly equipment, which has prevented the large-scale manufacturing and application of Ga 2 O 3 SBUV photodetectors. Of course, the solution-processed films have been widely applied to the preparation of photosensitive layers in Ga 2 O 3 SBUV detectors due to the simple process, low cost, and large-area growth, but most reported SBUV detectors based on this kind of films tend to exhibit low photoresponsivity and slow response. – Regarding this situation, it has been confirmed that some unintentional doping defects, such as oxygen vacancies, carbon (C) impurities, hydrogen (H) impurities, etc., are easily formed in the solution-processed Ga 2 O 3 films due to the extremely low formation energy. – These impurity defects that are prone to becoming carrier capture centers will be important factors attenuating the photoresponsivity and response speed. Therefore, decreasing the formation of unintentional impurity defects in Ga 2 O 3 films can be the key point to fabricate a SBUV detector with high photoresponsivity and high response speed.…”