Growth of wafer-scale chromium sulphide and selenide semiconductor films
Bing Yao, Weilin Liu, Xiaoxiang Zhou, Jiangfeng Yang, Xianlei Huang, Zihao Fu, Guowen Yuan, Yuefeng Nie, Yaomin Dai, Jie Xu, Libo Gao
Abstract
Abstract Two-dimensional (2D) transition metal chalcogenides have attracted enormous attention due to their stunning properties and great prospects for applications. Most of the reported 2D materials have layered structure, and non-layered transition metal chalcogenides are rare. Particularly, chromium chalcogenides are highly complexed in terms of structural phases. Researches on their representative chalcogenides, Cr 2 S 3 and Cr 2 Se 3 , are insufficient and most of them focus on individual crystal grains. In this study, large-scale Cr 2 S 3 and Cr 2 Se 3 films with controllable thickness are successfully grown, and their crystalline qualities are confirmed by multiple characterizations. Moreover, the thickness-dependent Raman vibrations are investigated systematically, presenting slight redshift with increasing thickness. The fundamental physical properties of grown Cr 2 S 3 and Cr 2 Se 3 films, including optical bandgap, activation energy and electrical properties, are measured with different thicknesses. The 1.9 nm thick Cr 2 S 3 and Cr 2 Se 3 films show narrow optical bandgap of 0.732 and 0.672 eV, respectively. The electrical properties of Cr 2 S 3 films demonstrate p -type semiconductor behaviours, while the Cr 2 Se 3 films exhibit no gate response. This work can provide a feasible method for growing large-scale Cr 2 S 3 and Cr 2 Se 3 films, and reveal fundamental information of their physical properties, which is helpful for future applications.