Preparation and photoelectric characterization of p-GeSe/p-WS2 heterojunction devices

Abstract

Abstract The construction of van der Waals (vdW) heterojunctions has attracted widespread attention for various strategies in the optoelectronic field due to their band structural advantages. Herein, novel p–p heterojunctions based on p-GeSe and p-WS2 flakes are fabricated on 300 nm-SiO2/Si substrates by means of mechanical exfoliation and micro-area fixed-point transfer of the GeSe flakes onto the WS2 flakes. The thickness and quality of the materials are determined by atomic force microscope and Raman spectroscopy. Considerable photoelectric characteristics are exhibited by exploring the performance of the heterojunctions under a 635 nm laser illumination. The photoresponsivity ( R λ ), specific detectivity ( D * ), and external quantum efficiency ( EQE ) of the heterojunctions are measured to be 195.70 mA W−1, 2.879 × 107 Jones, and 38.28%, respectively. The results indicate the strong potential of the p–p type heterojunctions composed of GeSe and WS2 flakes in photoelectric devices, and our work provides parameters and technical support for the development of vdW heterojunction devices.