A novel zinc diffusion process for the fabrication of high-performance GaSb thermophotovoltaic cells

This paper reports a novel zinc diffusion method for forming emitters in GaSb thermophotovoltaic cells. A closed quartz-tube diffusion system using Zn–Ga alloys as the diffusion source was designed to realize p-type doping in N-GaSb wafers. The surface diffusion region showing a high concentration of zinc was suppressed by this diffusion method, and the GaSb cells fabricated using this method showed good quantum efficiency in the near-infrared bands. Compared to that of the conventional pseudo-closed-box diffusion method, the controllability of the etch-back process after front-side metallization is significantly improved, and the cost of the cell fabrication is reduced because no protective gas is required during the diffusion process.