Evaluation of local free carrier concentrations in individual heavily-doped GaN:Si micro-rods by micro-Raman spectroscopy
Evaluation of local free carrier concentrations in individual heavily-doped GaN:Si micro-rods by micro-Raman spectroscopy
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DOI：
10.1063/1.4943079
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发表时间：
2016-03
影响因子：
4
通讯作者：
M. Mohajerani;S. Khachadorian;T. Schimpke;C. Nenstiel;J. Hartmann;J. Ledig;A. Avramescu;M. Strassburg;A. Hoffmann;A. Waag
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文献类型：
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作者：
M. Mohajerani;S. Khachadorian;T. Schimpke;C. Nenstiel;J. Hartmann;J. Ledig;A. Avramescu;M. Strassburg;A. Hoffmann;A. Waag
三维III族氮化物微结构正在被开发为未来光电器件的有希望的候选者。在这项研究中，我们展示了一种快速、直接的方法来局部评估单个 GaN:Si 微棒中的自由载流子浓度和晶体质量。通过采用微拉曼映射和分析 A1(LO)- 和 E1(LO)-声子等离子体耦合模式 (LPP–) 的低频分支，分别确定轴向和平面配置中的自由载流子浓度。由于沿微棒的逐渐掺杂分布，利用侧壁上的高度空间分辨率的映射来重建沿 GaN:Si 微棒的自由载流子浓度分布。尽管自由载流子浓度非常高，高于 1 × 1020 cm−3，但微棒仍显示出优异的晶体质量，且没有掺杂引起的应力。
Three-dimensional III-nitride micro-structures are being developed as a promising candidate for the future opto-electrical devices. In this study, we demonstrate a quick and straight-forward method to locally evaluate free-carrier concentrations and a crystalline quality in individual GaN:Si micro-rods. By employing micro-Raman mapping and analyzing lower frequency branch of A1(LO)- and E1(LO)-phonon-plasmon-coupled modes (LPP–), the free carrier concentrations are determined in axial and planar configurations, respectively. Due to a gradual doping profile along the micro-rods, a highly spatially resolved mapping on the sidewall is exploited to reconstruct free carrier concentration profile along the GaN:Si micro-rods. Despite remarkably high free carrier concentrations above 1 × 1020 cm−3, the micro-rods reveal an excellent crystalline quality, without a doping-induced stress.