Thin filmsofZn40Se60 were preparedbythevacuumthermalevaporationtechnique.Theinfluenceof
annealedtemperatureonthestructuralandopticalpropertieswasinvestigatedusingtheX-ray
diffraction(XRD),scanningelectronmicroscopy(SEM)andopticaltransmission.TheXRDstudiesshow
that theas-depositedfilmisamorphousinnature,butthecrystallinityimprovedwithincreasingthe
annealingtemperature.Furthermoretheparticlesizeandcrystallinityincreasedwhereasthedisloca-
tion andstrainsdecreasedwithincreasingtheannealingtemperature.SEMstudiesshowedthatthe
annealingtemperatureinducedchangesinthemorphologyoftheas-depositedsample.Variousoptical
constanthavebeencalculatedforas-depositedandannealedfilms.Themechanismoftheoptical
absorptionfollowstheruleofdirecttransition.Itwasfoundthat,theopticalenergygap(Eg) decreased
with increasingtheannealingtemperature.TheseresultscanbeinterpretedbytheDavisandMotte
model. Ontheotherhandthemaximumvalueoftherefractiveindex(n) isshiftedtowardthelong
wavelengthbyincreasingtheannealingtemperature.