Structural, optical and electrical properties of heavy ion irradiated CdZnO thin films

Abstract

The thin films of CdZnO were deposited on glass substrates using dc magnetron sputtering technique and investigated after heavy ion-irradiations of 100MeV Au ions with the fluences ranging from 1×1011ions/cm2 to 1×1013ions/cm2. The structural, optical and electrical properties of the irradiated and pristine films were studied by glancing angle X-ray diffraction (GAXRD), UV–vis–NIR spectroscopy and Hall effect measurement. The structural characterization using GAXRD pattern shows an enhancement of crystallinity up to the ion fluence of 5×1012ions/cm2, and the crystallinity decreases at the highest fluence of 1×1013ions/cm2 and these films exhibit hexagonal wurtzite crystal structure (002) with a c-axis orientation. The optical transmittance spectra reveals a red shift and the optical band gap decreases upon ion-irradiation with the minimum band gap at the ion fluence of 5×1012ions/cm2. The average transmittance of the thin film of CdZnO increases from 75% to 85% after irradiation (up to 5×1012ions/cm2). The atomic force microscopy image of the films reveals that roughness decreases up to the fluence of 5×1012ions/cm2 and increases at higher fluences. The films irradiated with a fluence of 5×1012ions/cm2 would show better electrical properties like low resistivity, high carrier concentration and mobility compared to other irradiated films.