Fundamental characterization studies of GaSb solar cells

Measured forward and reverse current versus voltage curves for GaSb cells at various temperatures and for different substrate dopant densities are modeled. The authors show that tunneling across a lower bandgap for reverse-biased GaSb cells allows nondestructive reverse current flow at low voltages. Thus, the GaSb IR cell doubles as a bypass diode, providing shading protection for the GaAs cell. Measured GaSb quantum yield curves are also modeled, and the resultant minority carrier diffusion lengths are compared with electron beam induced current measurements. It is found that the GaSb cell properties are consistent with predictions based on a direct gap single-crystal material