Band offset trends in IV-VI layered semiconductor heterojunctions

Ying Wang; Chen Qiu; Chenhai Shen; Lin Li; Kaike Yang; Zhongming Wei; Hui-Xiong Deng; Congxin Xia

doi:10.1088/1361-648X/ac5707

Band offset trends in IV-VI layered semiconductor heterojunctions

J Phys Condens Matter. 2022 Mar 9;34(19). doi: 10.1088/1361-648X/ac5707.

Authors

Ying Wang^{1

2}, Chen Qiu^{2

3}, Chenhai Shen¹, Lin Li¹, Kaike Yang⁴, Zhongming Wei², Hui-Xiong Deng², Congxin Xia¹

Affiliations

¹ Department of Physics, Henan Key Laboratory of Photovoltaic Materials, Henan Normal University, Xinxiang 453007, People's Republic of China.
² State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, People's Republic of China.
³ Beijing Computational Science Research Centre, Beijing 100094, People's Republic of China.
⁴ Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Synergetic Innovation Center for Quantum Effects and Applications, Department of Physics, Hunan Normal University, Changsha 410081, People's Republic of China.

PMID: 35189609
DOI: 10.1088/1361-648X/ac5707

Abstract

The band offsets between semiconductors are significantly associated with the optoelectronic characteristics and devices design. Here, we investigate the band offset trends of few-layer and bulk IV-VI semiconductors MX and MX₂(M = Ge, Sn; X = S, Se, Te). For common-cation (anion) systems, as the atomic number increases, the valence band offset of MX decreases, while that of MX₂has no distinct change, and the physical origin can be interpreted using band coupling mechanism and atomic potential trend. The band edges of GeX₂system straddle redox potentials of water, making them competitive candidates for photocatalyst. Moreover, layer number modulation can induce the band offset of GeSe/SnS and GeSe₂/GeS₂heterojunction undergoing a transition from type I to type II, which makes them suitable for optoelectronic applications.

Keywords: band coupling; band offsets; layered semiconductors; optoelectronic applications; photocatalyst.