Effect of swift heavy ion irradiation on the physical properties of CuIn(S 0.4Se 0.6) 2 alloy thin films prepared by solution growth technique

Alloy thin films of CuIn(S _0.4Se _0.6) ₂ material were deposited using the solution growth technique. The various deposition parameters such as pH of solution, time, concentration of ions and temperature have been optimized for the device grade thin films. The as-deposited films were annealed in a rapid thermal annealing (RTA) system at 450 °C in air for 5 min and subjected to high-energy Ag ion irradiations. Ag ion irradiation has been performed with an energy of 100 MeV at a fluency of 5×10 ¹² ions/cm ² on the thin film. The changes in optical and electrical properties that occurred before and after post-deposition treatments in CuIn(S _0.4Se _0.6) ₂ thin films were studied using X-ray diffraction (XRD) and AFM; increase in crystallinity was observed after annealing and irradiation. In addition, structural damages were observed in irradiated thin films. After annealing and irradiation, the surface roughness was seen to be increased. Decrease in resistivity was observed, which is consistent with the optical energy band gap. The results are explained by considering the high energy deposited due to the electronic energy loss upon irradiation, which modified the properties of the material.