六角星形MoSe_2双层纳米片的制备及其光致发光性能  

Synthesis and photoluminescence property of hexangular star MoSe_2 bilayer

作　　者：黄静雯[1,2] 罗利琼[1,2] 金波[1,2] 楚士晋[1,2] 彭汝芳[1,2] 

机构地区：[1]西南科技大学四川省非金属复合与功能材料重点实验室-省部共建国家重点实验室培育基地,绵阳621010 [2]西南科技大学材料科学与工程学院,绵阳621010

出　　处：《物理学报》2017年第13期225-231,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51327804);西南科技大学团队基金项目(批准号:14tdfk05)资助的课题~~

摘　　要：采用化学气相沉积法,以三氧化钼作为钼源,硒粉作为硒源,在H_2/Ar气氛下生长出硒化钼纳米片.扫描电镜、X射线衍射表征结果表明,MoSe_2产物呈六角星状,横向尺寸约10μm,具有很好的晶体质量和结构.拉曼光谱表征其结构,确定其为双层纳米片.研究表明,高温反应时间对双层纳米片的生长具有重要的影响.通过对双层纳米片的生长机理的探究,推测其经历了3个生长过程:在高温下,Mo源和Se源被气化成气态分子并发生硒化反应形成晶核;晶核呈三角形外延生长;当反应时间持续增加,在空间位阻效应的影响下,晶体以中心原子岛为核,外延耦合生长出第二层三角形,最终形成六角星状双层纳米片.光致发光光谱结果表明,六角星状MoSe_2双层纳米片在1.53 eV处具有直接带隙和1.78 eV处具有间接带隙,其较宽范围的激发光谱响应预测其在光电探测器件领域具有潜在的应用前景.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

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 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TQ136.12[化学工程—无机化工]