Wei Wei, Jin Chunming, Narayan Jagdish, Narayan Roger J
J Appl Phys. 2010 Jan 1;107(1):13510. doi: 10.1063/1.3271415. Epub 2010 Jan 7.
In this study, the optical and electrical properties of epitaxial single crystal gallium-doped Mg(x)Zn(1-x)O thin films grown on c-plane sapphire substrates by pulsed laser deposition were investigated. In these films, the Ga content was varied from 0.05 to 7 at. % and the Mg content was varied from 5 to 15 at. %. X-ray diffraction showed that the solid solubility limit of Ga in Mg(x)Zn(1-x)O is less than 3 at. %. The absorption spectra were fitted to examine Ga doping effects on bandgap and band tail characteristics. Distinctive trends in fitted bandgap and band tail characteristics were determined in films with Ga content below 3 at. % and Ga content above 3 at. %. The effects of bandgap engineering on optical transparency were evaluated using transmission spectra. Carrier concentration and Hall mobility data were obtained as functions of Ga content and Mg content. The electrical properties were significantly degraded when the Ga content exceeded 3 at. %. Correlations between conduction mechanisms and gallium doping of Mg(x)Zn(1-x)O thin films were described. In addition, the effect of bandgap engineering on the electrical properties of epitaxial single crystal gallium-doped Mg(x)Zn(1-x)O thin films was discussed.
在本研究中，对通过脉冲激光沉积在c面蓝宝石衬底上生长的外延单晶镓掺杂Mg(x)Zn(1-x)O薄膜的光学和电学性质进行了研究。在这些薄膜中，Ga含量在0.05至7原子百分比之间变化，Mg含量在5至15原子百分比之间变化。X射线衍射表明，Ga在Mg(x)Zn(1-x)O中的固溶度极限小于3原子百分比。对吸收光谱进行拟合以研究Ga掺杂对带隙和带尾特性的影响。在Ga含量低于3原子百分比和高于3原子百分比的薄膜中确定了拟合带隙和带尾特性的明显趋势。使用透射光谱评估带隙工程对光学透明度的影响。获得了载流子浓度和霍尔迁移率数据作为Ga含量和Mg含量的函数。当Ga含量超过3原子百分比时，电学性质显著退化。描述了Mg(x)Zn(1-x)O薄膜的导电机制与镓掺杂之间的相关性。此外，还讨论了带隙工程对外延单晶镓掺杂Mg(x)Zn(1-x)O薄膜电学性质的影响。
