Facile Fabrication of a Two-Dimensional TMD/Si Heterojunction Photodiode by Atmospheric-Pressure Plasma-Enhanced Chemical Vapor Deposition

A growth technique to directly prepare two-dimensional (2D) materials onto conventional semiconductor substrates, enabling low-temperature, high-throughput, and large-area capability, is needed to realize competitive 2D transition-metal dichalcogenide (TMD)/three-dimensional (3D) semiconductor heterojunction devices. Therefore, we herein successfully developed an atmospheric-pressure plasma-enhanced chemical vapor deposition (AP-PECVD) technique, which could grow MoS₂ and WS₂ multilayers directly onto PET flexible substrate as well as 4-in. Si substrates at temperatures of <200 °C. The as-fabricated MoS₂/Si and WS₂/Si heterojunctions exhibited large and fast photocurrent responses under illumination of a green light. The measured photocurrent was linearly proportional to the laser power, indicating that trapping and detrapping of the photogenerated carriers at defect states could not significantly suppress the collection of photocarriers. All the results demonstrated that our AP-PECVD method could produce high-quality TMD/Si 2D-3D heterojunctions for optoelectronic applications.