Effects of high-dose Ge ion implantation and post- implantation annealing on ZnO thin films

摘要

This paper reports that ion implantation to a dose of 1 x 10~(17) ions/cm~2 was performed on e-axis-orientated ZnO thin films deposited on (0001) sapphire substrates by the sol-gel technique. After ion implantation, the as-implanted ZnO films were annealed in argon ambient at different temperatures from 600 — 900℃. The effects of ion implantation and post-implantation annealing on the structural and optical properties of the ZnO films were investigated by x-ray diffraction (XR.D), photoluminescence (PL). It was found that the intensities of (002) peak and near band edge (NBE) exitonic ultraviolet emission increased with increasing annealing temperature from 600 — 900℃. The defect related deep level emission (DLE) firstly increased with increasing annealing temperature from 600 — 750℃, and then decreased quickly with increasing annealing temperature. The recovery of the intensities of NBE and DLE occurs at ～ 850℃ and ～ 750℃ respectively. The relative PL intensity ratio of NBE to DLE showed that the quality of ZnO films increased continuously with increasing annealing temperature from 600 — 900℃.