摘要
There has been growing research interest in the use of molybdenum disulfide in the fields of optoelectronics and energy harvesting devices, by virtue of its indirect-to-direct band gap tunability. However, obtaining large area thin films of MoS2 for future device applications still remains a challenge. In the present study, the amounts of the precursors （S and MOO3） were varied systematically in order to optimize the growth of highly crystalline and large area MoS2 layers by the chemical vapor deposition method. Careful control of the amounts of precursors was found to the key factor in the synthesis of large area highly crystalline flakes. The thickness of the layers was confirmed by Raman spectroscopy and atomic force microscopy. The optical properties and chemical composition were studied by photoluminescence （PL） and X-ray photoelectron spectroscopy. The emergence of strong direct excitonic emissions at 1.82 eV （A-exciton, with a normalized PL intensity of -55 × 10^3） and 1.98 eV （B-exciton, with a normalized PL intensity of -5 × 10^3） of the sample at room temperature clearly indicates the high luminescence quantum efficiency. The mobility of the films was found to be 0.09 cm^2/（V.s） at room temperature. This study provides a method for the controlled synthesis of high-quality two-dimensional （2D） transition metal dichalcogenide materials, useful for applications in nanodevices, optoelectronics and solar energv conversion.
在那里在收获设备的光电子和精力的领域里在铝二硫化物的使用一直在种研究兴趣，由它的 indirect-to-direct 乐队差距 tunability 的优点。然而，获得大区域瞬间的薄电影 < 潜水艇 class= “ a-plus-plus ” > 为未来设备应用的 2 </sub> 仍然是挑战。在现在的学习，先锋的数量(S 和哞 < 潜水艇 class= “ a-plus-plus ” > 3 </sub>) 系统地被改变以便优化高度水晶、大的区域瞬间的生长 < 潜水艇 class= “ a-plus-plus ” > 由化学蒸汽免职方法的 2 </sub> 层。先锋的数量的小心的控制在大区域的合成被发现到关键因素高度水晶的薄片。层的厚度被拉曼光谱学和原子力量显微镜学证实。光性质和化学作文被光致发光(PL ) 和 X 光检查光电子光谱学学习。在 1.82 eV 的强壮的直接激子的排出物的出现(A 激子，与 55 个 thout 事件的规范的 PL 紧张[1.84 ??? 隰酐鱠? 鎄颩 ???? 頿?? 鲰？？
