Formation of a ZnSe : In2O3 heterostructure by air annealing ZnSe-In thin film

A thin film of indium approximately 10 nm thick was deposited by thermal ev aporation onto a chemically deposited ZnSe thin film of thickness 0.16 mu m . Annealing the ZnSe-In films in air at 250 to 300 degrees C for 15 min res ulted in the formation of a ZnSe-In2O3 heterostructure, The In2O3 layer was approximately 10 nm thick with an average grain diameter of 20 nm, A sheet resistance of 4.5 k Omega/square was observed over the film surface which is attributed to a non-stoichiometric In2O3-x film formed on the surface, w ith an n-type conductivity of similar to 200 Omega(-1) cm(-1). Annealing at 300 degrees C or for a longer duration at 250 degrees C could reduce this conductivity through improve in the stoichiometry. The optical transmittanc e of the In2O3 film for the visible and near-infrared region was sc 80%. Th e underlying ZnSe film showed a direct bandgap of 2.7-2.75 eV, Etching in a dilute HCl solution removed the In2O3 him and revealed a near-intrinsic Zn Se film, showing electrical properties similar to those of the ZnSe films a nnealed at the same temperature, with sheet resistance similar to 10(13) Oh m/square Applications of the (i)ZnSe-(n)In2O3 heterastructure to the fabric ation of photonic devices are suggested.