RESUMEN
The structural characteristics and optical and electrical properties of molecular-beam-epitaxy (MBE) grown ZnS(0.8)Se(0.2) thin films on indium-tin-oxide (ITO) glass substrates were investigated in this work. The X-ray diffraction (XRD) results indicated that high quality polycrystalline ZnS(0.8)Se(0.2) thin film grown at the optimized temperature had a preferred orientation along the (111) planes. The transmission electron microscopy (TEM) cross-sectional micrograph of the sample showed a well defined columnar structure with lateral crystal dimension in the order of a few hundred angstroms. Ultraviolet (UV) photoresponsivity as high as 0.01 A/W had been demonstrated and for wavelengths longer than 450 nm, the response was down from the peak response by more than 3 orders of magnitude. The thin ZnS(0.8)Se(0.2) photosensor layer, with a wide energy gap and anisotropic electrical property, makes a transmission UV liquid crystal light valve (LCLV) with high resolution feasible.
RESUMEN
MBE growth of ZnS(x)Se(1 - x) thin films on ITO coated glass substrates were carried out using ZnS and Se sources with the substrate temperature ranging from 270 degrees C to 330 degrees C . The XRD theta/2theta spectra resulted from these films indicated that the as-grown polycrystalline ZnS(x)Se(1 - x) thin films had a preferred orientation along the (111) planes. The evaluated crystal sizes as deduced from the FWHM of the XRD layer peaks showed strong growth temperature dependence, with the optimized temperature being about 290 degrees C. Both AFM and TEM measurements of these thin films also indicated a similar growth temperature dependence. High quality ZnS(x)Se(1 - x) thin film grown at the optimized temperature had the smoothest surface with lowest RMS value of 1.2 nm and TEM cross-sectional micrograph showing a well defined columnar structure.
