Romanov Roman I, Zabrosaev Ivan V, Chouprik Anastasia A, Yakubovsky Dmitry I, Tatmyshevskiy Mikhail K, Volkov Valentyn S, Markeev Andrey M
Center of Shared Research Facilities, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141701, Russia.
Center for Photonics & 2D Materials, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141700, Russia.
Nanomaterials (Basel). 2023 Oct 6;13(19):2712. doi: 10.3390/nano13192712.
Metal-Organic CVD method (MOCVD) allows for deposition of ultrathin 2D transition metal dichalcogenides (TMD) films of electronic quality onto wafer-scale substrates. In this work, the effect of temperature on structure, chemical states, and electronic qualities of the MOCVD MoS films were investigated. The results demonstrate that the temperature increase in the range of 650 °C to 950 °C results in non-monotonic average crystallite size variation. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman spectroscopy investigation has established the film crystal structure improvement with temperature increase in this range. At the same time, X-Ray photoelectron spectroscopy (XPS) method allowed to reveal non-stoichiometric phase fraction increase, corresponding to increased sulfur vacancies (V) concentration from approximately 0.9 at.% to 3.6 at.%. Established dependency between the crystallite domains size and V concentration suggests that these vacancies are form predominantly at the grain boundaries. The results suggest that an increased Vs concentration and enhanced charge carriers scattering at the grains' boundaries should be the primary reasons of films' resistivity increase from 4 kΩ·cm to 39 kΩ·cm.
金属有机化学气相沉积法（MOCVD）能够将具有电子品质的超薄二维过渡金属二硫属化物（TMD）薄膜沉积到晶圆级衬底上。在本工作中，研究了温度对MOCVD法制备的MoS薄膜的结构、化学状态和电子品质的影响。结果表明，在650℃至950℃范围内温度升高会导致平均微晶尺寸呈非单调变化。原子力显微镜（AFM）、透射电子显微镜（TEM）和拉曼光谱研究表明，在此温度范围内，随着温度升高，薄膜晶体结构得到改善。同时，X射线光电子能谱（XPS）方法揭示了非化学计量相分数增加，对应于硫空位（V）浓度从约0.9原子百分比增加到3.6原子百分比。微晶畴尺寸与V浓度之间已确定的相关性表明，这些空位主要在晶界处形成。结果表明，V浓度增加以及晶界处电荷载流子散射增强应是薄膜电阻率从4kΩ·cm增加到39kΩ·cm的主要原因。
