Tunability of Physical Properties of Zn1-xCuxSe Nano Crystalline Thin Films With Copper Concentration and Ion Beam Analysis by Rutherford Backscattering Spectroscopy

Abstract

The accurate composition and concentration depth information of the as-deposited and annealed Zn1-xCuxSe films were recorded by Rutherford backscattering spectroscopy (RBS) technique. The films were grown on simple glass substrates by using close spaced sublimation technique. Precursor films, having thickness of about 250 to 300 nm, were afterward annealed in air atmosphere at temperatures of 200oC and 400oC for 1 hour. Structural characterization including crystal structure and orientation, stacking fault energy and surface morphology were calculated by using X-ray diffraction (XRD) and atomic force microscopy (AFM). Characterization of optical properties such as absorption coefficient, band gap energy estimation and dielectric constant was done by spectroscopic ellipsometer. A comparison of XRD results revealed that asdeposited and annealed films have polycrystalline nature with zinc-blende structure in the (111) plane. Stacking fault energy (SFE) of the films determined from XRD data decreases with increasing annealing temperature and also decreases by increasing Cu concentration up to 10% and then increases for 15% and 20% Cu concentration. AFM studies revealed that surface morphology is enhanced with increasing annealing temperature of 400oC. The band gap energy of the films determined using k spectra by spectroscopic ellipsometer increases while dielectric constant decreases with increasing annealing temperature.