2D/3D ZrS3/p-GaN heterostructure photodetector for dual-band and polarization-based optical information encryption

Abstract

Broadband and polarization-sensitive photodetection is essential for advanced optical imaging, encrypted communication, and multidimensional sensing. However, achieving simultaneous UV–visible dual-band detection and polarization sensitivity in a single photodetector remains a significant challenge due to material limitations. Herein, a multifunctional photodetector based on a ZrS₃/p-GaN 2D–3D heterojunction is demonstrated, integrating the strong ultraviolet (UV) absorption of GaN with the polarization-sensitive visible-light response of ZrS₃. The device covers a broad spectral range from UV to visible and exhibits clear polarization sensitivity around 490 nm, which is not achievable with conventional III–V or silicon-based 3D photodetectors. With these features, the device enables dual-band imaging and optical communication. Furthermore, a proof-of-concept application in image encryption and accurate decryption, with a recognition rate of 98 % for the decrypted image, was achieved using polarization as an encryption key and assisted by a convolutional neural network (CNN). This work provides an effective strategy to overcome the functional limitations of conventional photodetectors and presents a promising pathway for developing compact, multidimensional, and intelligent optoelectronic systems.