Optoelectronic properties of Ga1−xAlxN superlattice nanowires tuned by multilayer Al composition via first-principles

Abstract

Considering that the graded structure could generate an electric field, the structure and optoelectronic properties of [Formula: see text][Formula: see text]N superlattice nanowires are considered via first-principles. The structural stability and optoelectronic properties of single-component and component-graded nanowires are discussed. For [Formula: see text][Formula: see text]N superlattice nanowires, the formation energy decreases with increasing Al composition, resulting in a structure that tends to be stable. The [Formula: see text][Formula: see text]N superlattice model is more stable and the bond length changes more dramatically in the superlattice structure with bigger component divergence. The bandgap [Formula: see text] increases with increasing Al composition. The direct bandgap of [Formula: see text][Formula: see text]N superlattice nanowires is also affected by the nanowire sublayers. The absorption coefficient tends to increase with the increase of Al composition in the nanowires. These studies can serve as the basis for the preparation of ideal materials for deep ultraviolet photocathodes and improve the optoelectronic properties of deep ultraviolet photocathodes.