物理学报2017，Vol.66Issue(13)：252-259,8.DOI:10.7498/aps.66.137801
六角星形MoSe2双层纳米片的制备及其光致发光性能
Synthesis and photoluminescence property of hexangular star MoSe2 bilayer
摘要
Abstract
Transition metal dichalcogenides (TMDs) have received widespread attention because of their excellent performances in the field of optoelectronic, nanoelectronic device and photocatalytic exploration. The structures of TMDs can be expressed by the MX2, M =Mo, W;X =S, Se, Te, etc. As a typical TMD, MoSe2 has a graphene-like two-dimensional periodic structure with perfect physical, photoelcrtonic and catalytic properties. Currently, there are various methods to prepare the nanolevel MoSe2, such as the mechanical exfoliation, physical vapor deposition (PVD), hydrothermal method, chemical vapor deposition (CVD), etc, and most studies focused on regular triangular morphologies of the surfaces of different substrates. The new morphology, such as the hexangular star bilayer, has not been systematically investigated. In this study, the hexangular star MoSe2 nanosheets are successfully synthesized by using a simple CVD method in an atmosphere of mixed H2/Ar with a flow rate ratio of 1: 4. Molybdenum trioxide(MoO3) and selenium (Se) powders are chosen to be the Mo and Se source, respectively. Moreover, the structure of the obtained MoSe2 nanosheet is characterized by Raman, SEM, EDS, XRD and TEM. The results of Raman spectrum and SEM indicate that the hexangular star MoSe2 possesses a bilayer structure. The TEM characterization reveals that the MoSe2 is a single crystal with a hexagonal lattice structure and good quality. The heating time at high temperature has a remarkable influence on the MoSe2 bilayer growth process. The growth process of the hexangular star MoSe2 bilayer is inferred to experience a three-step process. First, Mo and Se sources are gasified into gaseous molecules and then the Mo molecules are selenized into the MoSe2 crystal nucleus under high temperature. Next, these crystal nucleus are in a triangular epitaxial growth under the action of carrier gas. As heating time increases, the space steric effect leads to different interlayer separations between the two MoSe2 layers in various stacking configurations, eventually forming a hexangular star bilayer. The PL result shows that the spectra split into two main emission peaks, i.e., the direct and indirect bandgaps of the hexangular star structure appearing at 1.53 eV (810.2 nm) and 1.78 eV (696.9 nm), respectively. It might be due to the spin-orbit coupling interaction between the double MoSe2 molecules. The wide spectral range of the MoSe2 bilayer indicates that it has a potencial application in the photoelectric detectors.关键词
六角星状MoSe2/化学气相沉积法/光致发光/空间位阻效应Key words
hexangular star MoSe2/chemical vapor deposition/photoluminescence/the repulsive steric effects引用本文复制引用
黄静雯,罗利琼,金波,楚士晋,彭汝芳..六角星形MoSe2双层纳米片的制备及其光致发光性能[J].物理学报,2017,66(13):252-259,8.基金项目
国家自然科学基金 (批准号: 51327804)和西南科技大学团队基金项目(批准号: 14tdfk05)资助的课题. Project supported by the National Natural Science Foundation of China (Grant No. 51327804) and Open Project of State Key Laboratory Cultivation Base for Nonmetal Composites and Functional, China (Grant No. 14tdfk05). （批准号: 51327804）
