材料科学
基质(水族馆)
电子迁移率
表面粗糙度
制作
场效应晶体管
帕利烯
杂质
光电子学
晶体管
纳米技术
复合材料
化学
电气工程
聚合物
电压
地质学
工程类
病理
海洋学
有机化学
替代医学
医学
作者
Bhim Chamlagain,Qing Li,Nirmal Ghimire,Hsun Jen Chuang,Meeghage Madusanka Perera,Honggen Tu,Yong Xu,Minghu Pan,Di Xaio,Jiaqiang Yan,David Mandrus,Zhixian Zhou
出处
期刊:ACS Nano
[American Chemical Society]
日期:2014-04-16
卷期号:8 (5): 5079-5088
被引量:169
摘要
We report low-temperature scanning tunneling microscopy characterization of MoSe2 crystals and the fabrication and electrical characterization of MoSe2 field-effect transistors on both SiO2 and parylene-C substrates. We find that the multilayer MoSe2 devices on parylene-C show a room-temperature mobility close to the mobility of bulk MoSe2 (100–160 cm2 V–1 s–1), which is significantly higher than that on SiO2 substrates (≈50 cm2 V–1 s–1). The room-temperature mobility on both types of substrates are nearly thickness-independent. Our variable-temperature transport measurements reveal a metal–insulator transition at a characteristic conductivity of e2/h. The mobility of MoSe2 devices extracted from the metallic region on both SiO2 and parylene-C increases up to ≈500 cm2 V–1 s–1 as the temperature decreases to ≈100 K, with the mobility of MoSe2 on SiO2 increasing more rapidly. In spite of the notable variation of charged impurities as indicated by the strongly sample-dependent low-temperature mobility, the mobility of all MoSe2 devices on SiO2 converges above 200 K, indicating that the high temperature (>200 K) mobility in these devices is nearly independent of the charged impurities. Our atomic force microscopy study of SiO2 and parylene-C substrates further rules out the surface roughness scattering as a major cause of the substrate-dependent mobility. We attribute the observed substrate dependence of MoSe2 mobility primarily to the surface polar optical phonon scattering originating from the SiO2 substrate, which is nearly absent in MoSe2 devices on parylene-C substrate.
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