We report the studies of ZnO:[Cu, Ga] thin films deposited by electron-beam evaporation method (EBE) and of ZnO:[Cu, Ga] thin films doped additionally with silver by means of close space sublimation technique (CSS). 

On first stage, ZnS and ZnS:[Cu, Ga] films were deposited onto glass substrates by EBE. Then, ZnO and ZnO:[Cu, Ga] films were prepared by an oxidization of ZnS and ZnS:[Cu, Ga] films at 600–650^oC in air or in wet air. Some ZnO:[Cu, Ga]  films were doped with silver. Ag doping was accomplished by CSS in air at atmospheric pressure.

The structural characteristics and surface morphology of the films were studied by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. Photoluminescence (PL) and PL excitation (PLE) spectra of the films were investigated in the temperature range of 30-300 K.  The excitation of emission was carried out by light from intrinsic absorption and extrinsic absorption regions. For PL and PLE measurements, we used an N2-laser
and an Xe-lamp, respectively.

As-deposited ZnS films were of sphalerite structure grown along a <111> direction. PL was not observed. At optimal conditions, the oxidation of ZnS and ZnS:[Cu, Ga] led to a complete transformation to ZnO and ZnO:[Cu, Ga] with a slightly marked grains orientation in a <0002> direction. Silver doping of ZnO:[Cu, Ga] films led to the mean grain orientation in a <0002> direction. XRD and AFM studies showed that the average grain size of the films oxidized in wet air (WA) were larger than of the films oxidized in dry air (DA).

PL intensity for the films after WA was higher than after DA. A strong influence of the water vapor on shape and intensity of the emission was observed. PL of ZnO:[Cu, Ga] films exhibits UV (380 nm) and green emission (500 nm). The intensity of UV band increases at additional Ag doping. The shape and intensity of PL depended on the doping and oxidation conditions. PLE spectra exhibited the maximum at 370–380 nm. Origin of observed emission bands is discussed.

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