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

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 (ASGa) is a highly stable surface point defect under As-rich density functional theory. Our results demonstrate that As antisite condition irrespective of bare and H-passivated GaAs nanowires. The formed As-Ga 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 nano-wires, we propose two feasible methods by reducing As chemical potential (or AS partial pressure) and passivating with appropriate surface species (e.g., NO2), respectively. This work provides a new insight into the origin of p-type doping limits and the guidance for the realization of highly efficient p-type doping in III-V semiconductor nanowires.