Vertical van der Waals heterojunction diodes comprising 2D semiconductors on 3D β-Ga2O3

Wide bandgap semiconductors such as gallium oxide (Ga2O3) have attracted much attention for their use in next-generation high-power electronics. Although single-crystal Ga2O3 substrates can be routinely grown from melt along various orientations, the influence of such orientations has been seldom reported. Further, making rectifying p-n diodes from Ga2O3 has been difficult due to lack of p-type doping. In this study, we fabricated and optimized 2D/3D vertical diodes on beta-Ga2O3 by varying the following three factors: substrate planar orientation, choice of 2D material and metal contacts. The quality of our devices was validated using high-temperature dependent measurements, atomic-force microscopy (AFM) techniques and technology computer-aided design (TCAD) simulations. Our findings suggest that 2D/3D beta-Ga2O3 vertical heterojunctions are optimized by substrate planar orientation (-201), combined with 2D WS2 exfoliated layers and Ti contacts, and show record rectification ratios (>10(6)) concurrently with ON-Current density (>10(3) A cm(-2)) for application in power rectifiers.

Automated summary

In this study, we successfully fabricated and optimized 2D/3D vertical diodes on beta-Ga2O3 by varying substrate planar orientation, choice of 2D material, and metal contacts. The quality of the devices was validated through high-temperature dependent measurements, atomic-force microscopy techniques, and technology computer-aided design simulations. The findings suggest that 2D/3D beta-Ga2O3 vertical heterojunctions optimized by specific factors show promising potential for application in power rectifiers.