Temperature dependence of the band gap of GaSb1-xBix alloys with 0 <x ≤ 0.042 determined by photoreflectance

GaSb_1-xBi_x layers with 0 <x ≤ 0.042 have been studied by photoreflectance in 15-290 K temperature range. We found that due to the incorporation of Bi atoms into the GaSb host, the E₀ band gap-related transition redshifts (∼30 meV per 1% Bi) and significantly broadens. The shift of the E₀ transition in the temperature range 10-270 K has been found to be ∼70 meV, very similar to the energy shift in GaSb over the same temperature range. We analyzed the energy and broadening of the E₀ transition using the Varshni and Bose-Einstein formulas and found that the Varshni and Bose-Einstein parameters of GaSb_1-xBi _x are similar to those of GaSb. Moreover we concluded that the inhomogeneities in GaSb_1-xBi_x alloys is less important than in dilute bismide arsenides since Bi atoms are more similar to Sb atoms (in electronegativities and ionic sizes). © 2013 AIP Publishing LLC.