Comparative studies of ZnO thin films grown by electron beam evaporation, pulsed laser and RF sputtering technique for optoelectronics applications

ZnO thin films are most promising materials for various emerging applications. In this report, we have compared the physical properties of ZnO thin films deposited at room temperature by three frequently used physical vapor deposition methods, namely, electron beam evaporation, pulsed laser deposition (PLD), and radio frequency (RF) sputtering. The structural, morphological, optical and electrical properties of the deposited ZnO thin films were compared systematically using X-ray diffraction, scanning electron microscopy, atomic force microscopy and UV–visible spectrophotometry. All the films showed polycrystalline nature, with the film deposited using PLD being found to be of highest crystalline quality. Uniformly distributed and densely packed particles were realized throughout the film for all the techniques. The films show notable transparent nature in the visible range of the electromagnetic spectrum. Distinctly visible UV emission was observed for the PLD and RF technique, indicating the suitability for making light-emitting diode and photodiode. E-beam-deposited films showed high porosity which is ideal for designing gas sensors.