Effect of 8 MeV electrons irradiation on carrier transport mechanism in ZnO thin films fabricated by sol-gel spin coating technique

The role of high energy particle (electron) irradiation on the structural, optical, and electrical properties of ZnO films with different irradiation dose rates (0 kGy, 1 kGy, and 5 kGy) are investigated in the present study. The deterioration of the crystallinity along (002) plane in irradiated ZnO films is observed due to redistribution of surface energy upon irradiation. Grain-Boundary conduction model is adopted to study the charge carrier transfer mechanism in ZnO films. The enhanced localized defect states below the conduction band in the irradiated films results in the band gap shrinkage due to band bending mechanism. The band bending in the irradiated films is further confirmed by the Debye length values. The enhanced optical loss in the irradiated films due to dominant optical scattering at grain boundaries confirms the rapid dissipation of the electromagnetic energy. The present work shed light on the effect of irradiation on the carrier transport mechanism and possible applications of ZnO films in the radiation environment.