Polarization Reversal of Group IV-VI Semiconductors with Pucker-Like Structure: Mechanism Dissecting and Function Demonstration.

Polarization imaging presents advantages in capturing spatial, spectral, and polarization information across various spectral bands. It can improve the perceptual ability of image sensors and has garnered more applications. Despite its potential, challenges persist in identifying band information and implementing image enhancement using polarization imaging. These challenges often necessitate integrating spectrometers or other components, resulting in increased complexities within image processing systems and hindering device miniaturization trends. Here, the characteristics of anisotropic absorption reversal are systematically elucidated in pucker-like group IV-VI semiconductors MX (M = Ge, Sn; X = S, Se) through theoretical predictions and experimental validations. Additionally, the fundamental mechanisms behind anisotropy reversal in different bands are also explored. The photodetector is constructed by utilizing MX as a light-absorbing layer, harnessing polarization-sensitive photoresponse for virtual imaging. The results indicate that the utilization of polarization reversal photodetectors holds advantages in achieving further multifunctional integration within the device structure while simplifying its configuration, including band information identification and image enhancement. This study provides a comprehensive analysis of polarization reversal mechanisms and presents a promising and reliable approach for achieving dual-band image band identification and image enhancement without additional auxiliary components.