Growth and characterization of buried GaSb p-n junctions for photovoltaic applications

Structures composed of a p++(Zn)GaAs layer deposited by MOVPE on a n(Te)-doped GaSb substrate were fabricated, with the purpose of obtaining GaSb p-n homo-junctions, through the diffusion of Zn into the substrate, for photovoltaic applications. Different Zn doping levels and post-growth annealing parameters were investigated. The junctions were characterized from the electrical point of view by I-V measurements, while Zn diffusion profiles were studied by SIMS analysis. The effective achievement of a GaSb buried junction, whose profile is characterized by a limited Zn diffusion into the substrate, was evidenced. Efficiency measurements by a solar simulator on 5x5 mm2 samples were also performed in order to investigate the photovoltaic properties of the structure.