RESUMO
We construct the two-dimensional (2D) excitonic solar cells based on type II vdW heterojunctions of Janus III-VI chalcogenide monolayers and investigate the performance of the device using the first principle. The calculated solar energy absorbance of In2SSe/GaInSe2and In2SeTe/GaInSe2heterojunctions is the order of 105cm-1. The predicted photoelectric conversion efficiency of the In2SeTe/GaInSe2heterojunction can reach up to 24.5%, which compares favorably with other previously studied 2D heterojunctions. The excellent performance of In2SeTe/GaInSe2heterojunction originates from the fact that the built-in electric field at the interface of In2SeTe/GaInSe2promote the flow of the photogenerated electrons. The results suggest that 2D Janus Group-III chalcogenide heterojunction can be a good candidate for new optoelectronic nanodevices.
RESUMO
Edge contact between two-dimensional materials and metal can achieve small contact resistance because of strong interaction. In this work, we investigated the electronic transport of in-plane (IP) heterojunctions based on Ti/WSSe and Sn/WSSe using first principle calculations. The results showed that the interface bonding and metallization are found on the IP Ti/WSSe and Sn/WSSe contact interface, indicating that the Ohmic contacts are formed between Ti, Sn and WSSe. Then, we constructed double-gate model to investigate the performance of the IP Ti and Sn contacted 5.1 nm WSSe Schottky barrier field-effect transistors (SBFETs). The calculated on-state current of the IP Ti contacted 5.1 nm WSSe SBFETs is 406.3 µA/µm. While, the on-state current of the Sn contacted 5.1 nm WSSe SBFETs reachs up to 1104.2 µA/µm, which is far beyond the requirements of the requirements of International Technology Roadmap for Semiconductor (ITRS) HP application targets. Our study will provide a guide for high performance transistors based on IP metal/WSSe configurations in the future.