CVD法单层MoS 2 在 209 Bi离子辐照下的损伤效应研究

Abstract

通过光学显微镜、拉曼光谱确定了CVD（化学气相沉积法）制备的不同厚度MoS2的层数，采用拉曼分析结合原子力显微镜观测分析了由HIRFL提供的高能209Bi离子辐照CVD制备的单层MoS2样品随辐照注量的损伤规律。随辐照注量增加，E2g1和A1g两种声子振动模式对应的拉曼峰逐渐蓝移，且拉曼特征峰强度减弱，这是由于带正电荷的209Bi辐照产生潜径迹型晶格缺陷吸附空气中氧分子而引入p型掺杂引起的。同时，在辐照注量为5×1010 ions/cm2的单层MoS2的AFM图像中观察到潜径迹主要以凹坑形式出现，与机械剥离法观测到的凸起径迹明显不同，分析了不同制备工艺对径迹形貌的影响。比较了机械剥离法制备MoS2样品的拉曼光谱和AFM成像的实验数据和结果，认为不同制备方法会影响单层或少层MoS2的电子密度。 The layer number of MoS2 with different thickness was determined by the optical microscope and Raman spectra. And the damage effect of the CVD (chemical vapor deposition) prepared single-layer MoS2 sample irradiated by 209Bi ions was analyzed by the combination of Raman analysis and AFM observations. With the increase of irradiation fluence, the Raman characteristic peaks of E2g1 and A1g corresponding to both phonon vibration modes gradually bluely shift, and the intensity of the peaks obviously decreased. This is due to the fact that the 209Bi ion irradiation results in the latent track type lattice defects and they adsorb the oxygen molecules in the air ended with the p-type doping. Meanwhile, from the AFM image of the mono-layer of irradiated MoS2 under the 5×1010 ions/cm2, it can been seen that latent tracks mainly occur in the form of pits, which different from the hillock tracks observed by mechanical stripping method. The influence of different preparation technology to the track morphology is analyzed. Compared with the Raman and AFM results of MoS2 prepared by mechanical stripping, it is considered that different preparation methods will affect the electron density in single or few layers of MoS2.