First-principles study on the structural stability and electronic properties of GaAs/Ga1−xAlxAs superlattice nanowires

Abstract

In this study, the first-principles method is used to study the structural stability and electronic properties of GaAs/Ga1−xAlxAs and AlxGa1−xAs/AlyGa1−yAs superlattice nanowires. Calculations show that GaAs/Ga1−xAlxAs superlattice nanowires with smaller Al component spacing have higher structural stability. The increase of Al composition will further weaken the stability of GaAs/Ga1−xAlxAs heterostructure nanowires. Compared with the pure GaAs nanowires, the work function of GaAs/Ga1−xAlxAs heterostructure nanowires is all reduced, indicating that the variable Al composition heterostructure can enhance the photoemission ability. In addition, heterostructures with different configurations exhibit different electronic properties. Moreover, a powerful built-in electric field is formed across the GaAs/AlxGa1−xAs superlattice interface, which will further promote the migration of photoelectrons from low Al composition layer to high Al composition layer. GaAs/Ga1−xAlxAs superlattice nanowires are promising to be the high-performance photocathode materials.