Water-Vapor-Mediated Close-Spaced Vapor Transport Growth of Epitaxial Gallium Indium Phosphide Films on Gallium Arsenide Substrates

Ga1-xInxP is a technologically important III-V ternary semiconductor widely utilized in commercial and record-efficiency solar cells. We report the growth of Ga1-xInxP by water-vapor-mediated close-spaced vapor transport. Because growth of III-V semiconductors in this system is controlled by diffusion of metal oxide species, we find that congruent transport from the mixed powder source requires complete annealing to form a single alloy phase. Growth from a fully alloyed source at water vapor concentrations of similar to 7000 ppm in H-2 at 850 degrees C affords smooth films with electron mobility of 1070 cm(2) V-1 s(-1) and peak internal quantum efficiency of similar to 90% for carrier collection in a nonaqueous photoelectrochemical test cell.