Broadband and High‐Sensitivity Photodetector Based on BiFeO3/Si Heterojunction. Issue 1 (4th November 2022)

• Record Type: Journal Article
• Authors: Lei, Lin; Liu, Lin; Lu, Xiaomei; Yan, Shuo; Hu, Xueli; He, Jiayi; Huang, Fengzhen
• Is Part Of: Advanced optical materials. Volume 11:Issue 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-04
• Subjects: BiFeO 3/Si -- broadband detection -- ferroelectric/semiconductor heterojunction -- high‐sensitivity -- photodetectors; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.202201893
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Photovoltaic devices based on ferroelectric materials have broad application prospects; however, there are also problems of narrow bandwidth and low sensitivity. In this paper, polycrystalline BiFeO3 (BFO) films are prepared directly on n‐Si (100) substrates to form ferroelectric/semiconductor heterostructures, the electrical response of which under weak light intensity (0.8 W m −2 ) is systematically investigated. Accompanied by the dielectric relaxation originated from photocarriers, the polarization of BFO increases while the coercive voltage decreases. Especially, current–voltage ( I–V ) curve under negative bias voltage changes obviously with illumination, and cyclically switchable photocurrent is detected at 0 V bias, with the on‐off ratio increasing for lower temperature. Although the photoresponse is detectable in the broad wavelength range of 275–1100 nm, it is more pronounced for visible light. It is considered that the built‐in electric field of the PN junction at the BFO/n‐Si interface drives the separation and migration of photocarriers, which in turn affects the interface barrier and the distribution of monovalent oxygen vacancies ( V O $V_{\rm{O}}^ \bullet $ ) in BFO while producing the photovoltaic effect. This work provides an effective route for developing photodetectors with high sensitivity and broadband detection. Abstract : This work reports a photodetector based on BiFeO3 /n‐Si heterojunctions. Under weak light intensity (0.8 W m −2 ), the detector shows photoresponse in a wide range of 275–1100 nm. With the decrease of temperature, the photoelectric on‐off ratio increases. This work provides a new idea for the development of photodetectors with high sensitivity and wide optical band.