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用等离子辅助分子束外延 (P MBE)的方法 ,在蓝宝石c平面上外延生长了MgxZn1 xO合金薄膜。在0≤x≤ 0 2范围内薄膜保持着ZnO的纤锌矿结构不变。X射线双晶衍射谱的结果表明生长的样品是单晶薄膜。据布喇格衍射公式计算得到 ,随着Mg含量的增加 ,薄膜的晶格常数c由 0 5 2 0 5nm减小到 0 5 1 85nm。室温光致发光谱出现很强的紫外近带发射 (NBE)峰 ,没有观察到深能级 (DL)发射 ,且随着Mg的掺入量的增加 ,紫外发射峰有明显的蓝移。透射光谱的结果表明 ,合金薄膜的吸收边随着Mg离子的掺入逐渐向高能侧移动 ,这与室温下光致发光的结果是相吻合的 ,并计算出随着x值增加 ,带隙宽度从 3 338eV逐渐展宽到3 6 82eV。通过研究Mg0 1 2 Zn0 88O样品的变温光谱 ,将紫外发射归结为束缚在施主能级上的束缚激子发射。并详细地研究了在整个温度变化过程中 ,束缚激子的两个不同的猝灭过程以及谱线的半峰全宽与温度变化的关系。
Plasma-assisted molecular beam epitaxy (P MBE) was used to epitaxially grow MgxZn1xO alloy thin films on sapphire c-plane. The film maintains the wurtzite structure of ZnO in the range of 0≤x≤0 2. The results of the X-ray double crystal diffraction spectrum show that the grown sample is a single crystal thin film. According to the Bragg diffraction formula, the lattice constant c decreases from 0 5 2 0 5 nm to 0 5 1 85 nm with the increase of Mg content. There was a strong ultraviolet near-band emission (NBE) peak in room temperature photoluminescence spectrum. No deep level (DL) emission was observed. With the increase of Mg content, there was a clear blue shift of UV emission peak. The results of transmission spectra show that the absorption edge of the alloy thin film gradually shifts to the higher energy side with the Mg ions incorporated, which is consistent with the result of photoluminescence at room temperature. It is calculated that as the x value increases, the band gap width Gradually widening from 3 338eV to 3 6 82eV. By studying the temperature changing spectra of Mg0 1 2 Zn0 88O samples, the UV emission is reduced to the bound exciton emission bound to the donor level. The two different quenching processes of bound excitons and the relationship between the full width at half maximum (FWHM) of the line and the temperature change were studied in detail during the whole temperature change.