Regulation of Bi2O3 phase structure improves the self-powered UV-blue dual‐band photoresponse of Bi2O3/TiO2 photodetectors and the imaging application

Abstract

Bi2O3 semiconductors with excellent optical and electrical properties can be used in photodetectors (PDs). For different phase structures of Bi2O3 with corresponding optoelectronic properties in Bi2O3 due to differences in crystal structure and energy band structure, it is important to control the phase structure to obtain high-performance Bi2O3-based PDs. Herein, Bi2O3 nanosheet films with α and β phase structures controlled by the annealing temperature are deposited on the surface of TiO2 nanorod arrays (NRs) to construct ultraviolet (UV)-blue self-powered PDs. The effects of the energy band structure, Fermi level and carrier mobility of Bi2O3 films with different phase structures on the performance of Bi2O3/TiO2 PDs are investigated by combining theoretical calculations and experimental. The β-Bi2O3/TiO2 PDs with strong built-in electric field, large carrier mobility, small interfacial transfer resistance and long carrier lifetime exhibit excellent photoresponse characteristics. The PD demonstrates a responsivity of 26.7 mA W−1 and detectivity of 5.93 × 1011 Jones under 365 nm illumination. In addition, the imaging application of β-Bi2O3/TiO2 PD is explored by extending the photocurrent mapping values of a single PD unit to a complex array of optical information image processing in complex environments utilizing the UV-blue dual-band self-powered photoresponse properties of the PDs.