Van der Waals Nonlinear Photodetector with Quadratic Photoresponse

With unique electronic and optical attributes and broadened the functionalities of photodetectors. Here, we report a quadratically nonlinear photodetector (QNPD) composed of a van der Waals (vdW) stacked GaSe/InSe heterostructure. Compared with the reported 2D material-based photodetectors, the extra second-harmonic generation (SHG) process in GaSe/InSe leads to the quadratically nonlinear function between photocurrent and optical intensity, extending the photodetection wavelength from 900 to 1750 nm. The QNPD is highly sensitive to the variation of optical intensity with improved spatial resolution. With the light-light interaction in SHG converted into electrical signal directly, we also demonstrate the QNPD as an autocorrelator for measuring ultrafast pulse widths and an optoelectronic mixer of two modulated pulses for signal processings. The simultaneous involvement of light-light interaction and photoelectric conversion in the vdW stacked QNPD promises its potential to simplify the optoelectronic systems.

Automated summary

A quadratically nonlinear photodetector (QNPD) composed of a van der Waals (vdW) stacked GaSe/InSe heterostructure is reported in this study. The QNPD exhibits unique electronic and optical attributes and extends the photodetection wavelength range from 900 to 1750 nm due to the extra second-harmonic generation (SHG) process in GaSe/InSe. It is highly sensitive to the variation of optical intensity and can be used as an autocorrelator for measuring ultrafast pulse widths and an optoelectronic mixer for signal processing.