Broadband and Bipolar Photoresponse of BaTiO 3 /p-Si Heterostructures

Abstract Due to the unidirectional conductivity of semiconductor heterojunctions, there's always a trade-off between broadband response and specific wavelength identification in conventional photodetectors. Here, this limitation is broken by constructing BaTiO 3 /p-Si ferroelectric/semiconductor heterostructures. On the one hand, BaTiO 3 film and p-Si substrate complementally absorb light of different wavelength range, achieving broadband photoresponse from ultraviolet to near-infrared. On the other hand, the depolarization field of the BaTiO 3 layer and the built-in electric field at the BaTiO 3 /p-Si interface point oppositely, enabling bidirectional transport of photocarriers and specific identification of ultraviolet light. Based on this simple BaTiO 3 /p-Si heterostructures with two distinct photodetection modes, five logic operations were demonstrated. This work opens a new avenue for the design of self-powered multifunctional optoelectronic devices.