异质结
材料科学
接触电阻
量子隧道
热离子发射
凝聚态物理
肖特基势垒
半导体
肖特基二极管
离域电子
相(物质)
兴奋剂
纳米技术
光电子学
二极管
图层(电子)
电子
化学
物理
量子力学
有机化学
作者
Adam Pfeifle,Marcelo A. Kuroda
出处
期刊:Physical Review Materials
[American Physical Society]
日期:2019-12-24
卷期号:4 (2)
被引量:2
标识
DOI:10.1103/physrevmaterials.4.024002
摘要
Contact resistance of semiconducting transition metal dichalcogenides has been shown to decrease in lateral heterojunctions formed with their metallic phases but its origins remain elusive. Here we combine first principles and quantum transport calculations to rationalize the contact resistance of these structures in terms of phase, composition (WTe2, MoTe2, WSe2, and MoSe2), and length of the channel. We find that charge injection in metallic 1T'-WTe2/1T'-MoTe2 junctions is nearly ideal as electrode Bloch states remain delocalized through the channel. Mixtures of 1T' selenides and tellurides depart from this scenario due to the momentum mismatch between states in the lead and channel. In semiconducting channels, the large Schottky barriers degrade the electrical contacts. Around band edges, contact resistance values are about an order of magnitude lower than those obtained experimentally suggesting that doping and phase-engineering could be employed to overcome this issue. We predict that transport regime in these junctions shifts from thermionic emission to tunneling for channels shorter than 3 nm at room temperature. We also discuss the presence of states at the metal/semiconductor interfaces. By underpinning mechanisms to control the contact resistance in heterogeneous two-dimensional materials, this work proves valuable towards the development of devices suitable for optoelectronics and phase-change materials applications.
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