AgGaSe2 : A highly photoconductive material

High resistivity single crystals of AgGaSe2 were grown by the horizontal Bridgman technique. The near band edge photoconductivity of the grown crystal at room temperature was found to be up to 2×104 times higher than the dark conductivity, under the illumination of 10−3 W/cm2. The photoconductivity spectrum consists primarily of three peaks, which are attributed to the transitions from Γ7Γ7(A), Γ6Γ6(B) and Γ7Γ7(C) states of valence band to the conduction band Γ6Γ6. The crystal field splitting and the spin–orbit splitting were determined from these peak energy positions of the photoconductivity spectrum.