Low Temperature Synthesis of Embedded AgInSe2 Nano-crystallites in an Amorphous Matrix

The present study reports the effect of thermal annealing on AgInSe2 thin films deposited by thermal evaporation method from the AgInSe2 ingot, prepared by melt quenching technique. The as-prepared film was annealed at 200 degrees C for 1 hr in Se atmosphere. XRD pattern of the annealed film revealed the formation of nano-crystallites of AgInSe2 with crystallite size 18.7 nm, whereas the as prepared film was amorphous. The annealed AgInSe2 film has chalcopyrite structure i.e. c/a = 1.92 approximate to 2. The optical transmittance spectra of the as prepared and annealed AgInSe2 thin films exhibit interference due to uniform film thickness. The crystal field splitting band gap decreased from 1.73 eV to 1.59 eV on annealing.