Effect of surface treatment with different sulfide solutions on the ultrafast dynamics of photogenerated carriers in GaAs(1Â 0Â 0)

► Free carriers dynamics in GaAs treated with various sulfide solutions are studied. ► Treatment with sulfide solutions decreases surface recombination velocity in GaAs. ► Alcoholic solution reduces surface recombination in greater extent than aqueous one. ► Mechanism of interaction of HS− ions with GaAs is different in different solvents.