Carrier transport through near-ideal interface for WSe2 van der Waals homojunction diode

Abstract

Abstract Transition-metal dichalcogenides are promising alternatives to conventional materials for next-generation devices owing to their unique characteristics. Because efficient doping is difficult, in designing devices, more than two materials are typically heterogeneously junctioned via van der Waals (vdW) bonds. However, unintended effects at the vdW heterojunction due to lattice mismatch or trap-assisted transport limit the device performance. In this study, we fabricated a vdW homojunction p–n diode with elementally doped WSe2. The device made of pristine WSe2 exhibited forward diode characteristics with an ideal transport characteristic. When WSe2 was doped with the p-dopant bis(trifluoromethane) sulfonimide, the carrier transport mechanism changed from diffusion to tunneling. The device rectified the forward current with a high rectification ratio of 2 × 105 at 300 K. This study provides a comprehensive understanding of the carrier transport mechanism in a high-performance backward vdW homojunction diode.