Alloyed 2D Metal–Semiconductor Heterojunctions: Origin of Interface States Reduction and Schottky Barrier Lowering

• DOI: 10.1021/acs.nanolett.6b02893
• Publication Date: 2016-08-23T12:55:37Z
• Authors: Yonghun Kim; Ah Ra Kim; Jin Ho Yang; Kyoung Eun Chang; Jung-Dae Kwon; Sun Young Choi; Jucheol Park; Kang Eun Lee; Dong-Ho Kim; Sung Mook Choi; Kyu Hwan Lee; Byoung Hun Lee; Myung Gwan Hahm; Byungjin Cho
• Keywords: 0103 physical sciences; 01 natural sciences

The long-term stability and superior device reliability through the use of delicately designed metal contacts with two-dimensional (2D) atomic-scale semiconductors are considered one of the critical issues related to practical 2D-based electronic components. Here, we investigate the origin of the improved contact properties of alloyed 2D metal-semiconductor heterojunctions. 2D WSe2-based transistors with mixed transition layers containing van der Waals (M-vdW, NbSe2/WxNb1-xSe2/WSe2) junctions realize atomically sharp interfaces, exhibiting long hot-carrier lifetimes of approximately 75,296 s (78 times longer than that of metal-semiconductor, Pd/WSe2 junctions). Such dramatic lifetime enhancement in M-vdW-junctioned devices is attributed to the synergistic effects arising from the significant reduction in the number of defects and the Schottky barrier lowering at the interface. Formation of a controllable mixed-composition alloyed layer on the 2D active channel would be a breakthrough approach to maximize the electrical reliability of 2D nanomaterial-based electronic applications.