Favourable tuning of optical absorbance, bandgap and surface roughness of ZnO thin films by C ion implantation at the critical angle
R.V. Hariwal, Hitendra K. Malik, Ambika Negi, K. Asokan
Abstract
Low energy ion implantation with exquisite control of angle allows manipulating the applications of thin films. Here we present a favourable and efficient strategy of 50 keV Carbon ion implantations on ZnO thin films at three different tilt angles 0°, 30° and 60°. This plays a significant role in tuning of optical absorbance, bandgap, grain size and surface roughness simultaneously. The TRIM simulations are performed to elucidate the theoretical understanding and to compare the modifications in the physical properties using different characterization tools. These experimental results demonstrate that the ion implantations at 30° result in a significant reduction of 89% in the grain size and 35% reduction in the optical transmittance along with an improvement of 25% in the surface roughness of these thin films. The optical bandgap is also tuned from 3.27 to 3.20 eV. These results establish a new approach in designing the exotic materials with lower grain size, lower bandgap and smoother surface along with higher absorbance of ultraviolet (UV) light that will help increasing the data storage capacity and getting higher energy efficiency with reduced UV light emissions.