【摘要】 采用等离子辅助电子束蒸发技术制备高纯金属锌膜,然后在氧气气氛下经高温热处理得到氧化锌的多晶薄膜。X射线衍射谱的结果表明:未经热氧化样品由金属锌和氧化锌纳米晶组成,随着热氧化温度的升高氧化锌纳米晶粒长大,形成纳米氧化锌多晶薄膜且薄膜结晶性增强;光致发光谱表明:样品均具有较强的紫外自由激子发光。由于未经热氧化样品中氧化锌纳米晶粒较小,具有较强的量子限域效应,因而经高温氧化后样品发光峰有较大红移。随着热氧化温度的进一步升高,束缚激子发射随热氧化温度升高而减弱,且发光峰位随热氧化温度升高出现蓝移;变温光致发光谱表明:紫外发光主要来自自由激子发射。更多还原

【Abstract】 We report a simple method for preparing polycrystalline ZnO thin films by thermal oxidation of metallic Zn films, which were prepared by plasmaassisted Ebeam evaporation.Xray diffraction (XRD) and photoluminescence (PL) spectra were used to characterize the structural and optical properties of the thin films.XRD indicate that there are ZnO nanoparticles exist in the asgrown Zn film result from O2 plasma oxidation.With the annealing temperatures increasing, the grain sizes gradually increase and the quality of the hexagonal wurtzite structural ZnO thin films are evolution.The photoluminescence spectra show a strong nearbandedge (NBE) emissions with a weak deep level (DL) emission.Because of the quantum confinement effect and the dispersion of the grain size, the full width at half maximum (FWHM) of the photoluminescence (PL) peaks for the asgrown film is more wide and the PL peak position is shorter than that of the annealed ZnO films.Among samples of annealed ZnO films, the PL intensity of the bound exciton reduces with the increase of the thermal oxidation temperature, which drive UV PL peaks to shorter wavelength.The dependence of PL spectra on temperature from 82K to 300K for ZnO thin film annealed at 600℃ indicates that the bound exciton emission decrease and PL peaks exhibit redshift with the increase of annealing temperature.Peak position of the freeexciton emission is a function of temperature from 82～220K.The theoretical simulation to the experimental data is obtained by using Eq.:E(T)=E(0)-αT2/(T+β).The consequence of the theoretical fit agrees well with the reported value.更多还原