Study of confined coherent acoustic phonon modes in a free-standing cubic GaN membrane by femtosecond spectroscopy
Study of confined coherent acoustic phonon modes in a free-standing cubic GaN membrane by femtosecond spectroscopy
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DOI：
10.1063/1.4931495
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发表时间：
2015-09
影响因子：
4
通讯作者：
Chuan He;M. Grossmann;D. Brick;M. Schubert;S. Novikov;C. T. Foxon;V. Gusev;A. Kent;T. Dekorsy
中科院分区：
文献类型：
--
作者：
Chuan He;M. Grossmann;D. Brick;M. Schubert;S. Novikov;C. T. Foxon;V. Gusev;A. Kent;T. Dekorsy
通过飞秒泵浦探针光谱在亚微米厚的独立立方 GaN 膜中激发和检测受限纵向相干声声子模式。飞秒激光激发后，在时域中观察和研究了频率高达100 GHz的布里渊振荡和厚度振荡。我们发现在 400 nm 光激发下膜发生初始膨胀。我们的实验结果证实了早期现有的理论预测和实验观察，即立方氮化镓的静水变形势为正。
Confined longitudinal coherent acoustic phonon modes are excited and detected in a sub-μm-thick free-standing cubic GaN membrane by femtosecond pump-probe spectroscopy. After fs laser excitation, Brillouin oscillation and thickness oscillation with frequencies up to 100 GHz are observed and studied in the time domain. We found an initial expansion of the membrane upon optical excitation at 400 nm. Our experimental results confirmed earlier existing theoretical predictions and experimental observations that the hydrostatic deformation potential of cubic GaN is positive.