Phase-engineered low-resistance contacts for ultrathin MoS2 transistors
Phase-engineered low-resistance contacts for ultrathin MoS2 transistors
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DOI：
10.1038/nmat4080
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发表时间：
2014-12-01
期刊：
影响因子：
41.2
通讯作者：
Chhowalla, Manish
中科院分区：
文献类型：
--
作者：
Kappera, Rajesh;Voiry, Damien;Chhowalla, Manish
超薄二硫化钼（MoS2）因其有限的能带隙和不存在悬空键而成为一种有趣的层状半导体。然而，沉积在半导体 2H 相上的金属通常会形成高电阻（0.7 k Omega mu m-10 k Omega mu m）接触，导致肖特基限制输运。在这项研究中，我们证明MoS2的金属1T相可以在半导体2H相纳米片上局部诱导，从而在零栅极偏压下将接触电阻降低至200-300Ωμm。在空气中制造和测试的具有 1T 相电极的场效应晶体管 (FET) 表现出类似于 50 cm(2)V(-1)s(-1) 的迁移率值、每十倍频低于 100mV 的亚阈值摆幅值、>10(7) 的开/关比、接近于 100 mu A mu m(-1) 的驱动电流以及出色的电流饱和度。不同金属的沉积对 FET 性能的影响有限，表明 1T/2H 界面控制载流子注入沟道。我们基于 MoS2 相工程的策略还提高了电气特性的可重复性。
Ultrathin molybdenum disulphide (MoS2) has emerged as an interesting layered semiconductor because of its finite energy bandgap and the absence of dangling bonds. However, metals deposited on the semiconducting 2H phase usually form high-resistance (0.7 k Omega mu m-10 k Omega mu m) contacts, leading to Schottky-limited transport. In this study, we demonstrate that the metallic 1T phase of MoS2 can be locally induced on semiconducting 2H phase nanosheets, thus decreasing contact resistances to 200-300 Omega mu m at zero gate bias. Field-effect transistors (FETs) with 1T phase electrodes fabricated and tested in air exhibit mobility values of similar to 50 cm(2)V(-1)s(-1), subthreshold swing values below 100mV per decade, on/of ratios of >10(7), drive currents approaching similar to 100 mu A mu m(-1), and excellent current saturation. The deposition of different metals has limited influence on the FET performance, suggesting that the 1T/2H interface controls carrier injection into the channel. An increased reproducibility of the electrical characteristics is also obtained with our strategy based on phase engineering of MoS2.