Ultralow contact resistance between semimetal and monolayer semiconductors
Ultralow contact resistance between semimetal and monolayer semiconductors
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DOI：
10.1038/s41586-021-03472-9
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发表时间：
2021-05-13
期刊：
影响因子：
64.8
通讯作者：
Kong, Jing
中科院分区：
文献类型：
--
作者：
Shen, Pin-Chun;Su, Cong;Kong, Jing
先进的超硅电子技术既需要沟道材料，也需要发现超低电阻接触（1，2）。原子薄的二维半导体具有实现高性能电子器件的巨大潜力（1，3）。然而，由于金属诱导的间隙状态（MIGS）（4-7），金属-半导体界面处的能量势垒-其从根本上导致高接触电阻和差的电流输送能力-迄今为止限制了二维半导体晶体管的改进（2，8，9）。在这里，我们报告半金属铋和半导体单层过渡金属dichalcogenides（TMD）的MIGS充分抑制和TMD中的简并态自发形成接触铋之间的欧姆接触。通过这种方法，我们在单层MoS 2上实现了零肖特基势垒高度、123欧姆微米的接触电阻和1，135微安/微米的导通电流密度;据我们所知，这两个值分别是迄今为止记录的最低和最高值。我们还表明，良好的欧姆接触可以形成在各种单层半导体，包括二硫化钼，WS 2和WSe 2。我们报道的接触电阻是二维半导体的一个实质性的改进，并接近量子极限。这项技术揭示了高性能单层晶体管的潜力，相当于最先进的三维半导体，使进一步的设备缩小和扩展摩尔laws.Electric接触的单层半导体上的半金属铋，以抑制金属诱导的间隙状态，从而具有非常低的接触电阻和零肖特基势垒高度。
Advanced beyond-silicon electronic technology requires both channel materials and also ultralow-resistance contacts to be discovered(1,2). Atomically thin two-dimensional semiconductors have great potential for realizing high-performance electronic devices(1,3). However, owing to metal-induced gap states (MIGS)(4-7), energy barriers at the metal-semiconductor interface-which fundamentally lead to high contact resistance and poor current-delivery capability-have constrained the improvement of two-dimensional semiconductor transistors so far(2,8,9). Here we report ohmic contact between semimetallic bismuth and semiconducting monolayer transition metal dichalcogenides (TMDs) where the MIGS are sufficiently suppressed and degenerate states in the TMD are spontaneously formed in contact with bismuth. Through this approach, we achieve zero Schottky barrier height, a contact resistance of 123 ohm micrometres and an on-state current density of 1,135 microamps per micrometre on monolayer MoS2; these two values are, to the best of our knowledge, the lowest and highest yet recorded, respectively. We also demonstrate that excellent ohmic contacts can be formed on various monolayer semiconductors, including MoS2, WS2 and WSe2. Our reported contact resistances are a substantial improvement for two-dimensional semiconductors, and approach the quantum limit. This technology unveils the potential of high-performance monolayer transistors that are on par with state-of-the-art three-dimensional semiconductors, enabling further device downscaling and extending Moore's law.Electric contacts of semimetallic bismuth on monolayer semiconductors are shown to suppress metal-induced gap states and thus have very low contact resistance and a zero Schottky barrier height.