ZnO epitaxial thin films were grown on p-type Si(100) substrates by dual ion beam sputtering deposition system. The crystalline quality, surface morphology, optical and electrical properties of as-deposited ZnO thin films at different growth temperatures were studied. Substrate temperature was varied from 100 to 600 C at constant oxygen percentage O2/(O2 + Ar) % of 66.67 % in a mixed gas of Ar and O2 with constant chamber pressure of 2.75 × 10-4 mBar. X-Ray diffraction analyses revealed that all the films had (002) preferred orientation. The minimum value of stress was reported to be -0.32 × 1010 dyne/cm2 from ZnO film grown at 200 C. Photoluminescence measurements demonstrated sharp near-band-edge emission (NBE) was observed at ∼375 nm along with deep level emission (DLE) in the visible spectral range at room temperature. The DLE Peak was found to have decrement as ZnO growth temperature was increased from 200 to 600 C. The minimum FWHM of the NBE peak of 16.76 nm was achieved at 600 C growth temperature. X-Ray photoelectron spectroscopy study revealed presence of oxygen interstitials and vacancies point defects in ZnO film grown at 400 C. The ZnO thin film was found to be highly resistive when grown at 100 C. The ZnO films were found to be n-type conducting with decreasing resistivity on increasing substrate temperature from 200 to 500 C and again increased for film grown at 600 C. Based on these studies a correlation between native point defects, optical and electrical properties has been established.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Materials Science: Materials in Electronics|
|State||Published - Jul 2013|
Bibliographical noteFunding Information:
Acknowledgments This work is partially supported by Department of Science and Technology (DST) Fast Track Scheme for Young Scientist No. SR/FTP/ETA-101/2010. This work is also supported by DST Science and Engineering Research Board (SERB) project number SR/S3/EECE/0142/2011 and Council of Scientific and Industrial Research (CSIR) project number 22(0608)/12/EMR-II. The authors thank Vikas sahu of LMPD lab, RRCAT, Indore for PL measurements. We also thank Dr. Mukul Gupta and Dr. S. R. Barman of UGC-DAE-CSR, Indore for XRD and XPS measurements respectively. AFM measurements are done at RRCAT, Indore.