快重离子辐照对MoS_2热导率的影响研究

Evolution of the Thermal Conductivity of MoS_2 Induced by Swift-heavy Ion Irradiation

利用0.97 GeV的209Bi离子辐照二硫化钼(MoS_2)晶体,辐照注量范围为1×1010～1×1012ions/cm^2,结合原子力显微镜(AFM)观测和Raman光谱分析研究了快重离子辐照对MoS_2热导率的影响。实验结果显示,快重离子辐照在MoS_2中产生了潜径迹,较高激光功率下的Raman测试使样品局部温度升高,导致E12g和A1g峰随注量增加向低波数方向移动,且峰形展宽。引入了通过改变激光功率测量Raman光谱得到MoS_2热导率的计算方法,获得了不同辐照注量下MoS_2的热导率的定量分析结果,随注量增加,热导率不断降低,从未辐照样品的563 W/m K下降到1×1012ions/cm^2辐照时的132 W/mK。

Molybdenum disulphide（MoS2） was irradiated by 0.97 GeV209 Bi ions with the fluence of 1×1010to 1 × 1012ions/cm2. The irradiation effect on the thermal conductivity of MoS2 was analyzed by atomic force microscope（AFM） and Raman spectroscopy. The experimental results show that hillock-like latent tracks are observed on irradiated MoS2 by AFM. The measurement of MoS2 by Raman spectrometer with high laser power results in the increase of local temperature of MoS2, which cause the downshift of peaks position and broadening of E12 gand A1g peak. Furthermore, according to Raman spectra measured at different laser power, thermal conductivity of MoS2 before and after irradiation was calculated, which show that the thermal conductivity of MoS2 decreases with increasing fluence, from 563 to 132 W/m K for pristine and 1 × 1012ions/cm2 irradiated MoS2, respectively.