Large-scale m-GeS2 grown on GaN for self-powered ultrafast UV photodetection

Ultraviolet (UV) photodetection has been of great importance in the fields of aerospace, space communications, and remotely sensed images. However, conventional UV photodetectors (PDs) have been facing intrinsic drawbacks of complicate structural issues and interference from ambient visible light. Therefore, wide bandgap semiconductors have attracted significant attention. Herein, self-powered PDs based on the monolithic germanium disulfide (m-GeS2)/gallium nitride (GaN) pn heterojunction have been proposed with a large-size m-GeS2 over 2 cm2. The electronic and optical properties of the m-GeS2/GaN heterojunction are investigated via experiments and first-principles methods. The PDs reveal an impressive performance in self-powered response and high responsivity and detectivity of 16.8 mA W−1 and 1.03 × 1011 Jones, respectively. Further analyses determined that the PDs show an ultrafast photoresponse with a rise and fall time of < 0.30 and 1.10 ms at 365 nm. Consequently, this study provides a feasible method for the synthesis of large-sized m-GeS2 and demonstrates its enormous potential in high-performance, self-powered UV photodetection.