Chemical vapor deposition growth of monolayer MoSe sub(2) nanosheets

• Published in: Nano research Vol. 7; no. 4; pp. 1 - 7
• Main Authors: Shaw, Jonathan C, Zhou, Hailong, Chen, Yu, Weiss, Nathan O, Liu, Yuan, Huang, Yu, Duan, Xiangfeng
• Format: Journal Article
• Language: English
• Published: 01.04.2014
• Subjects: Band spectra; Chemical vapor deposition; Monolayers; Multilayers; Nanostructure; Semiconductors; Spectroscopy; Two dimensional
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-014-0417-z

The synthesis of two-dimensional (2D) layered materials with controllable thickness is of considerable interest for diverse applications. Here we report the first chemical vapor deposition growth of single- and few-layer MoSe sub(2) nanosheets. By using Se and MoO sub(3) as the chemical vapor supply, we demonstrate that highly crystalline MoSe sub(2) can be directly grown on the 300 nm SiO sub(2)/Si substrates to form optically distinguishable single- and multi-layer nanosheets, typically in triangular shaped domains with edge lengths around 30 mu m, which can merge into continuous thin films upon further growth. Micro-Raman spectroscopy and imaging was used to probe the thickness-dependent vibrational properties. Photoluminescence spectroscopy demonstrates that MoSe sub(2) monolayers exhibit strong near band edge emission at 1.55 eV, while bilayers or multi-layers exhibit much weaker emission, indicating of the transition to a direct band gap semiconductor as the thickness is reduced to a monolayer. [Figure not available: see fulltext.]