Effect of Mg doping on the structural and free-charge carrier properties of InN films
Effect of Mg doping on the structural and free-charge carrier properties of InN films
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DOI：
10.1063/1.4871975
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发表时间：
2014-04-28
影响因子：
3.2
通讯作者：
Darakchieva, V.
中科院分区：
文献类型：
--
作者：
Xie, M. -Y.;Ben Sedrine, N.;Darakchieva, V.
本文对分子束外延生长的两组掺镁InN薄膜的自由电荷载流子和结构特性进行了全面的研究。自由电子和空穴浓度、迁移率和等离子体激元展宽参数由红外椭圆偏振光谱仪确定。用高分辨X射线衍射仪和原子力显微镜测定了薄膜的晶格参数、微观结构和表面形貌。在两组InN薄膜中发现了一致的自由电荷载流子类型的结果，推测当[mg]小于或类似于9.0×10(19)cm(-3)时，可以获得p型电导。讨论了自由电荷载流子性质随镁离子浓度的系统变化与扩展缺陷密度和生长模式的关系。通过对薄膜的结构特征和自由电子浓度的比较，揭示了扩展缺陷和点缺陷对InN中n型电导率的影响。它还允许建议获得具有相对较高的电子迁移率和较低的缺陷密度的补偿InN材料的途径。确定了发生极性反转和闪锌矿Inn形成的镁浓度临界值。最后，研究了镁掺杂对薄膜晶格参数的影响，并讨论了不同掺杂对薄膜应变的贡献。(C)2014 AIP出版有限责任公司。
We present a comprehensive study of free-charge carrier and structural properties of two sets of InN films grown by molecular beam epitaxy and systematically doped with Mg from 1.0 x 10(18) cm(-3) to 3.9 x 10(21) cm(-3). The free electron and hole concentration, mobility, and plasmon broadening parameters are determined by infrared spectroscopic ellipsometry. The lattice parameters, microstructure, and surface morphology are determined by high-resolution X-ray diffraction and atomic force microscopy. Consistent results on the free-charge carrier type are found in the two sets of InN films and it is inferred that p-type conductivity could be achieved for 1.0 x 10(18) cm(-3) less than or similar to [Mg] less than or similar to 9.0 x 10(19) cm(-3). The systematic change of free-charge carrier properties with Mg concentration is discussed in relation to the evolution of extended defect density and growth mode. A comparison between the structural characteristics and free electron concentrations in the films provides insights in the role of extended and point defects for the n-type conductivity in InN. It further allows to suggest pathways for achieving compensated InN material with relatively high electron mobility and low defect densities. The critical values of Mg concentration for which polarity inversion and formation of zinc-blende InN occurred are determined. Finally, the effect of Mg doping on the lattice parameters is established and different contributions to the strain in the films are discussed. (C) 2014 AIP Publishing LLC.