Effect of doping on the far-infrared intersubband transitions in nonpolar m-plane GaN/AlGaN heterostructures
Effect of doping on the far-infrared intersubband transitions in nonpolar m-plane GaN/AlGaN heterostructures
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DOI：
10.1088/0957-4484/27/14/145201
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发表时间：
2016-04
期刊：
影响因子：
3.5
通讯作者：
C. Lim;A. Ajay;C. Bougerol;J. Lähnemann;F. Donatini;J. Schörmann;E. Bellet-Amalric;D. Browne;M. Jimenez-Rodriguez;E. Monroy
中科院分区：
文献类型：
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作者：
C. Lim;A. Ajay;C. Bougerol;J. Lähnemann;F. Donatini;J. Schörmann;E. Bellet-Amalric;D. Browne;M. Jimenez-Rodriguez;E. Monroy
本文评估了Si掺杂对非极性m-面GaN/AlGaN量子威尔斯阱（QW）特性的影响，该QW是为远红外波段的子带间（ISB）吸收而设计的。当掺杂浓度达到3 × 1012 cm−2时，结构分析显示量子阱均匀，界面突变，没有外延诱导缺陷。阴极射线荧光光谱证实了沿着生长方向的多个量子阱的均匀性。将量子阱中的掺杂密度从1 × 1011 cm-2增加到3 × 1012 cm-2会导致光致发光的加宽以及合金中激子局域化能量的降低。此外，观察到ISB吸收的增强，沿着吸收峰的蓝移和加宽。ISB吸收的幅度在掺杂水平约为1 × 1012 cm−2时饱和，蓝移和加宽的增加小于理论预测的掺杂水平较高的样品。这是由自由载流子的存在下，由于费米能级的能量的增加，在激发的电子能级解释。
This paper assesses the effects of Si doping on the properties of nonpolar m-plane GaN/AlGaN quantum wells (QWs) designed for intersubband (ISB) absorption in the far-infrared spectral range. For doping levels up to 3 × 1012 cm−2, structural analysis reveals uniform QWs with abrupt interfaces and no epitaxially induced defects. Cathodoluminescence spectroscopy confirms the homogeneity of the multiple QWs along the growth direction. Increasing the doping density in the QWs from 1 × 1011 cm−2 to 3 × 1012 cm−2 induces a broadening of the photoluminescence as well as a reduction of the exciton localization energy in the alloy. Also, enhancement of the ISB absorption is observed, along with a blue shift and widening of the absorption peak. The magnitude of the ISB absorption saturates for doping levels around 1 × 1012 cm−2, and the blue shift and broadening increase less than theoretically predicted for the samples with higher doping levels. This is explained by the presence of free carriers in the excited electron level due to the increase of the Fermi level energy.