Reconfigurable and Broadband Polarimetric Photodetector

The sensitive detection of light polarization besides the intensity and wavelength, can provide a new degree of freedom for more and clearer information of imaging targets in night, fog, and smoke environment. However, the conventional filter-integrated polarimetric photodetectors suffer from the complicated fabrication process and limited spectral range. Herein, broadband and polarization-sensitive photodetectors are achieved with reconfigurable operation mode, utilizing the linear dichroism and narrow band gap of 2D As0.4P0.6 with in-plane anisotropic structure. In As0.4P0.6-MoTe2 heterojunction device, both photo-gating and photovoltaic modes are operated and switchable, contributing to high responsivity (1590 A W-1 at 405 nm and 14.7 A W-1 at 1550 nm) and ultrafast speed (25 mu s) in the wide spectral band (405-1550 nm). Interestingly, an optical reversal is observed on both linear dichroism and polarimetric photocurrent due to the wavelength-dependent polarization reverse nature of the As0.4P0.6 flakes. The dichroism ratio of photocurrent can be modulated from unity to approximate to 10 by varying the gate voltage, enabling the reconfigurable detection mode from polarization-independence to polarization-susceptibility. This study demonstrates a new prototype device comprising low symmetric van der Waals heterostructure, possessing the gate-tunability on both photo-gain and dichroism ratio, toward high performance, reconfigurable, broadband, and polarization-resolved photodetection and imaging applications.

Automated summary

In this study, broadband and polarization-sensitive photodetectors are achieved using the linear dichroism and narrow band gap of 2D As0.4P0.6. By varying the gate voltage, the absorption ratio of the photocurrent can be modulated from 1 to approximately 10, enabling a reconfigurable detection mode from polarization-independence to polarization-susceptibility.