Andrzejewski D, Marx M, Grundmann A, Pfingsten O, Kalisch H, Vescan A, Heuken M, Kümmell T, Bacher G
Werkstoffe der Elektrotechnik and CENIDE, University of Duisburg-Essen, Bismarckstraße 81, D-47057 Duisburg, Germany.
Nanotechnology. 2018 Jul 20;29(29):295704. doi: 10.1088/1361-6528/aabbb9. Epub 2018 Apr 5.
Fabrication of transition metal dichalcogenides (TMDCs) via metalorganic chemical vapor deposition (MOCVD) represents one of the most attractive routes to large-scale 2D material layers. Although good homogeneity and electrical conductance have been reported recently, the relation between growth parameters and photoluminescence (PL) intensity-one of the most important parameters for optoelectronic applications-has not yet been discussed for MOCVD TMDCs. In this work, MoS is grown via MOCVD on sapphire (0001) substrates using molybdenum hexacarbonyl (Mo(CO), MCO) and di-tert-butyl sulphide as precursor materials. A prebake step under H atmosphere combined with a reduced MCO precursor flow increases the crystal grain size by one order of magnitude and strongly enhances PL intensity with a clear correlation to the grain size. A decrease of the linewidth of both Raman resonances and PL spectra down to full width at half maxima of 3.2 cm for the E Raman mode and 60 meV for the overall PL spectrum indicate a reduced defect density at optimized growth conditions.
通过金属有机化学气相沉积（MOCVD）制备过渡金属二硫属化物（TMDCs）是大规模二维材料层最具吸引力的途径之一。尽管最近有报道称其具有良好的均匀性和导电性，但对于MOCVD法制备的TMDCs，生长参数与光致发光（PL）强度（光电子应用中最重要的参数之一）之间的关系尚未得到讨论。在这项工作中，使用六羰基钼（Mo(CO)₆，MCO）和二叔丁基硫醚作为前驱体材料，通过MOCVD在蓝宝石（0001）衬底上生长MoS₂。在H₂气氛下的预烘烤步骤与降低的MCO前驱体流量相结合，使晶粒尺寸增加了一个数量级，并强烈增强了PL强度，且与晶粒尺寸有明显的相关性。对于E₂g Raman模式，拉曼共振和PL光谱的线宽均降至半高宽为3.2 cm⁻¹，对于整体PL光谱，半高宽降至60 meV，这表明在优化的生长条件下缺陷密度降低。
