Controllable spin rectification behavior of vertical and lateral VSe2/WSe2 heterojunction Schottky diodes

Abstract

Heterojunctions (HJs) based on two-dimensional (2D) transition metal dichalcogenides are considered promising candidates for next-generation electronic and optoelectronic devices. Here, vertical (V-type) and lateral (L-type) HJ diodes based on metallic 1T-VSe₂ and semiconducting 2H-WSe₂ with out-of-plane and in-plane contacts are designed. First-principles quantum transport simulations reveal that both V- and L-type VSe₂/WSe₂ HJ diodes form p-type Schottky contacts. Under zero gate voltage, V-type VSe₂/WSe₂ HJ Schottky diodes exhibit superior spin rectification behavior compared to L-type, with rectification ratios approaching 10⁹ and 10⁶, respectively. At 300 K, the ideality factor of the V-type diode is lower than that of the L-type and reaches the ideal state at 478 and 510 K, respectively. Notably, positive gate voltage can reverse the rectification direction in both diodes and weaken the rectifying effect in V-type devices. Conversely, negative gate voltage significantly increases the current in both diodes and enhances the rectification ratio of the L-type device to 10⁹. These findings provide insights into the spin-dependent rectification behavior of V- and L-type VSe₂/WSe₂ HJs in Schottky diodes, offering theoretical guidance for exploring magnetic nanoscale devices based on 2D materials.