We have investigated the influence of in situ annealing on the optical, electrical, structural and morphological properties of ZnO thin films prepared on p-type Si(100) substrates by dual ion beam sputtering deposition (DIBSD) system. X-ray diffraction (XRD) measurements showed that all ZnO films have (002) preferred orientation. Full-width at half-maximum (FWHM) of XRD from the (002) crystal plane was observed to reach to a minimum value of 0.139° from ZnO film, annealed at 600 °C. Photoluminescence (PL) measurements demonstrated sharp near-band-edge emission (NBE) at ~ 380 nm along with broad deep level emissions (DLEs) at room temperature. Moreover, when the annealing temperature was increased from 400 to 600 °C, the ratio of NBE peak intensity to DLE peak intensity initially increased, however, it reduced at further increase in annealing temperature. In electrical characterization as well, when annealing temperature was increased from 400 to 600 °C, room temperature electron mobility enhanced from 6.534 to 13.326 cm2/V s, and then reduced with subsequent increase in temperature. Therefore, 600 °C annealing temperature produced good-quality ZnO film, suitable for optoelectronic devices fabrication. X-ray photoelectron spectroscopy (XPS) study revealed the presence of oxygen interstitials and vacancies point defects in ZnO film annealed at 400 °C.
Bibliographical noteFunding Information:
1Discipline of Electrical Engineering, Hybrid Nanodevice Research Group, Indian Institute of Technology, Indore 453 441, India 2Department of Atomic Energy (UGC DAE), Consortium for Scientific Research, University Grants Commission, Indore 452 001, India
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. We are also grateful to the atomic force microscopy (AFM) facility equipped at Sophisticated Instrument Centre (SIC), IIT Indore.
- In situ annealing