CuAlSe2 Thin Films Obtained by Chalcogenization

Abstract

Abstract. CuAlSe2 thinfilms havebeen synthesizedbychalcogenization ofthin Cu and Al layerssequentiallydepositedbyevaporation under vacuum. Itisshownthat CuAlSe2films are obtained with some Cu2-rise andSe phases present at thesurfaceThese phases are suppressedbyannealing under vacuum and chemical etching in a KCNsolution. Attheendoftheprocess, XRDspectrum demonstratesthat textured CuAlSe2 filmshave been obtainedwith preferential orientationofthe crystallitesalong the (l12) direction. Thegapthefilmsis2.7eV as expected. The films are nearlystoichiometric~ but theirsurface is quiterough The XPSspectra show that some Nadiffusesfromthe substrate towardthesurface during the annealing process. However, this Nais etched by KCN.1. Introduction TernaryI-III-VI2chalcopyrite semiconductorshavereceivedconsiderableattentioninrecentyearsbecauseoftheir applications in photovoltaic devices.Ifthe CuInSe2 isthe most extensively studied compound of family, some other ternary chalcopyrites haveattractedmuchattention