Van der Waals metal-semiconductor junction: Weak Fermi level pinning enables effective tuning of Schottky barrier

Two-dimensional (2D) semiconductors have shown great potential for electronic and optoelectronic applications. However, their development is limited by a large Schottky barrier (SB) at the metal-semiconductor junction (MSJ), which is difficult to tune by using conventional metals because of the effect of strong Fermi level pinning (FLP). We show that this problem can be overcome by using 2D metals, which are bounded with 2D semiconductors through van der Waals (vdW) interactions. This success relies on a weak FLP at the vdW MSJ, which is attributed to the suppression of metal-induced gap states. Consequently, the SB becomes tunable and can vanish with proper 2D metals (for example, H-NbS2). This work not only…

• UD
  U.S. Department of Energy

  Awards: ID0EQJAG6449, -AC02-05CH11231, AC36-08GO28308, 05CH11231, -AC36-08GO28308, AC02-05CH11231, DE-AC02, 08GO28308, DE-AC02-05CH11231, DE-AC02-
• OO
  Office of Science

  Awards: ID0ESKAG6451, AC02-05CH11231, -AC02-05CH11231, DE-AC02, DE-AC36-08GO28308
• OO
  Office of Energy Efficiency and Renewable Energy

  Awards: AC02-05CH11231, ID0EBKAG6450, AC36-08GO28308, DE-AC36-08GO28308, DE-AC02-05CH11231, DE-261 EE0006336
• NR
  National Renewable Energy Laboratory

  Awards: AC36-08GO28308, DE-AC02-05CH11231, DE-AC36-08GO28308