Electric field and strain engineering tuning of 2D Gr/-Ga₂O₃ van der Waals heterostructures

Functional electrical devices based on two-dimensional (2D) materials can benefit from the considerable potential of van der Waals heterostructures (vdWHs). We investigated the electrical characteristics, contact behavior, and optical performance of 2D metal-semiconductor vdWHs comprised of graphene and alpha-Ga2O3, in which alpha-Ga2O3 possesses two polarization states that are diametrically opposed to one another (alpha-Ga2O3 up arrow and alpha-Ga2O3 down arrow). Utilizing first-principles calculations, Gr/alpha-Ga2O3 up arrow vdWHs have n-type Schottky contacts, while Gr/alpha-Ga2O3 down arrow vdWHs have n-type Ohmic contacts. Applying strains and electric fields efficiently regulates the band alignment between these two substances, which can reach different contact types. Moreover, our research findings suggest that vertical strains and electric fields can boost the carrier concentration in the Gr layer to about similar to 10(13) cm(-2). Besides, the Gr/alpha-Ga2O3 vdWHs have much higher optical absorption than the isolated alpha-Ga2O3 monolayers in the visible and UV spectral regions. Consequently, the fact that Gr/alpha-Ga2O3 vdWHs are capable of attaining controlled contact types makes them especially well-suited for use in applications involving electrical and optoelectronic devices.