CBE colloquia - The Growth of 2D Semiconductor and Its Multi-dimensional Photodetection
Compared to traditional refrigerated (such as HgCdTe, InSb) and unrefrigerated infrared detection materials (Si, InGaAs), 2D materials, especially the transition metal dichalcogenides (TMDCs), exhibit rich physical properties due to their atomic-level thickness, high carrier mobility, and extremely easy-to-adjust electronic structure, making it possible to realize the miniaturization, portability, high performance, and low power consumption of infrared detection materials.
Based on this topic, our group focus on the growth of these novel 2D materials, including MoS2, PtSe2 and PtS. During the growth, we mainly tune the surface nanostructure, percussor and the setup, and finally realized: 1) 4-inch MoS2 continue film; 2) 300-μm single-crystal PtSe2. Then, we focus on the electronic/photoelectrical property and their tunability. It was found that the junction promotes the separation of photogenerated electrons and holes due to the formation of a built-in electric field. The photoexcitation originating from the inter-band will extent the photoresponse range from visible to NIR. Some 2D materials such as In2Se3 shows both light-sensitive and polarization-sensitive behavior, facilitating to fabricate multi-dimensional photodetection. Nowadays, MoS2 already realize wafer-scale growth, however its isotropic optical property limited its further application. Regarding this issue, we also studied the modulation such as micro-structure hybridization and bi-layers twisting, which exhibits the potential ability in future multi-dimensional photodetection.
Dr. Zegao Wang is a full professor at College of Materials Science and Engineering, Sichuan University. He obtained a bachelor’s degree in Electronic Science and Technology, and a PhD in Microelectronic and Solid-state Electronics from University of Electronic Science and Technology of China, China, in 2008 and 2014, respectively. Then, he worked at Interdisciplinary Nanoscience Center, Aarhus University, Denmark, as postdoctoral researcher. In 2018, he was employed as tenure-track professor in Sichuan University and started individual investigation. He was appointed as a full professor in 2023 and vice dean of College of Materials Science and Engineering in 2024. Dr. Wang’s research mainly focuses on two-dimensional materials such as MoS2, WSe2, PtSe2 film and wafer growth, and study their applications in photodetection, gas sensing, energy and environment.