Role of microstructure on optical properties in high-uniformity In1-xGaxAs nanowire arrays: Evidence of a wider wurtzite band gap
Role of microstructure on optical properties in high-uniformity In1-xGaxAs nanowire arrays: Evidence of a wider wurtzite band gap
复制标题
DOI：
10.1103/physrevb.87.205303
复制
发表时间：
2013-05-10
影响因子：
3.7
通讯作者：
Koblmueller, Gregor
中科院分区：
文献类型：
--
作者：
Morkoetter, Stefanie;Funk, Stefan;Koblmueller, Gregor
在三元半导体纳米线中获取基本的结构-性质相关性是一项具有挑战性的工作，通常受到巨大的组成不均匀的限制。在这里，我们研究了在成分非常均匀的硅衬底上生长的强周期性In1-xGaxAs纳米线阵列，通过透射电子显微镜、拉曼光谱和光致发光光谱来确定微结构特征(晶相和堆积顺序)对声子和光学性质的影响。根据Ga含量和生长动力学的不同，我们发现纳米线的微结构从纤锌矿为主的堆积结构一致地转变为无序的层状堆积结构，随着拉曼模式的加宽，从富In到更富Ga的In1-xGaXAs的成分变化一致。因此，更高质量的纤锌矿堆积导致了光致发光强度的增强，最引人注目的是，发射能量相对于1-xGaXAs相的体相蓝移了30-40 meV。这一发现支持了理论上预测的组份调谐纤锌矿型In1-xGaxAs的较大禁带能量。
Accessing fundamental structure-property correlations in ternary semiconductor nanowires is a challenging endeavor often limited by large compositional inhomogeneities. Here, we investigate strongly periodic In1-xGaxAs nanowire arrays grown on Si with very high compositional uniformity to identify the role of microstructural features (crystal phase and stacking order) on the phonon and optical properties via transmission electron microscopy, Raman, and photoluminescence spectroscopy. Depending on Ga content and growth kinetics, we show that the nanowire microstructure changes consistently from a wurtzite-dominated stacking to a disordered layer stacking, with broadened Raman modes, upon tuning the composition from In-rich to more Ga-rich In1-xGaxAs. Consequently, higher-quality wurtzite stacking leads to enhanced photoluminescence emission intensities and, most strikingly, a blue-shift in the emission energy of similar to 30-40 meV with respect to the bulk In1-xGaxAs phase. This finding supports the theoretically predicted larger band-gap energy of composition-tuned wurtzite-type In1-xGaxAs.