Impact of Surface Point Defects on Electronic Properties and p-Type Doping of GaAs Nanowires

Abstract

Gallium arsenide (GaAs) nanowires possess a great potential as a fundamental building block for the next-generation electronic and optoelectronic devices, but their applications are limited by the p-type doping. Improving the p-type doping efficiency of GaAs nanowires depends on understanding the doping limits and developing effective methods to reactive p-type dopants. Here the stability of various surface point defects and their role in electronic structure and p-type doping of GaAs nanowires are studied by using first-principles calculation within density functional theory. Our results demonstrate that As antisite (AsGa) is a highly stable surface point defect under As-rich condition irrespective of bare and H-passivated GaAs nanowires. The formed AsGa defects bring deep donor-type levels into the band gap, which is responsible for the deactivation of p-type dopants in GaAs nanowires. To suppress the impact of AsGa defects on the p-type doping of GaAs nanowires, we propose two feasible methods by reduc...