Electrostatic gating-driven transition from Schottky contact to p–n junction in moiré patterned Ars/Gra heterostructures

Abstract

Atomically thin van der Waals (vdW) heterostructures provide a practical platform to study mutual interactions between the two individual layers, and the resulting subtle electrons transfer and concomitant electronic band characteristics. Herein, using first-principles calculations and analyses, we demonstrate that there is no interlayer net charge transfer within the moiré patterned arsenene/graphene (Ars/Gra) heterostructure because the binding between them arises predominantly from the physical polarization of intralayered electrons. Substantively, according to the Schottky–Mott rule, the moiré patterned Ars/Gra heterostructure retains its Schottky contact. Strikingly, electrostatic gating can drive the interlayer charge transfer from the Ars layer to the Gra layer, giving rise to p-type Ars and n-type Gra, and then forming a moiré patterned Ars/Gra p–n junction when the electric field exceeds the threshold of 0.54 V Å⁻¹. Doping an isovalent Sb atom to the Ars layer can create impurity bands above the valence band maximum of Ars, which significantly reduces the electric field to 0.48 V Å⁻¹ to realize an identical p–n junction. Such featured electronic phase transition from the moiré patterned Schottky contact to p–n junction is absent in the reported ordered stacking Ars/Gra heterostructures. We also observed that different moiré patterns of Ars/Gra have a substantial impact on the electron/hole Fermi velocity and asymmetry factor. The mapped carrier transport trend also supports the finding of the electric phase transition. These findings provide new insights into the electrostatic gating driven electronic phase transition and could be useful for the future design of graphene-based vdW heterostructures.