Improving the rectification characteristics of GaN/Si heterojunction by constructing an interpenetrating two-phase interface layer

Abstract

Heterojunctions with patterned or nanostructured interfaces usually show specific advantages in developing high-performance optoelectronic devices, especially for those composed of two kinds of semiconductors with large lattice and thermal mismatches. In this study, a heterojunction with complex interface structures is prepared by growing GaN on a patterned Si hierarchical structure, the Si nanoporous pillar array (Si-NPA). The most prominent feature of GaN/Si-NPA is its interpenetrated two-phase interface layer composed of massive Si and GaN nanocrystallites. Compared with GaN/Si heterojunction with planar interface, GaN/Si-NPA shows improved electrical properties such as increased breakdown voltage and lowered leakage current density. The property improvement is ascribed to the promotion of the junction quality and the lowering of the overall defect density, both of which are attributed to the reduction of the strain and stress through a three-dimensional release mode. The research provides a viable approach for constructing high-quality heterojunctions by using largely mismatched semiconductors, which might find extensive applications in designing and fabricating optoelectronic devices.