Universität Leipzig, Institut für Experimentelle Physik II, Linnéstraße 5, 04103 Leipzig, Germany.
Nanotechnology. 2016 Jun 3;27(22):225702. doi: 10.1088/0957-4484/27/22/225702. Epub 2016 Apr 22.
We report on the temporal lasing dynamics of high quality ZnO nanowires using the time-resolved micro-photoluminescence technique. The temperature dependence of the lasing characteristics and of the corresponding decay constants demonstrate the formation of an electron-hole plasma to be the underlying gain mechanism in the considered temperature range from 10 K to 300 K. We found that the temperature-dependent emission onset-time ([Formula: see text]) strongly depends on the excitation power and becomes smallest in the lasing regime, with values below 5 ps. Furthermore, the observed red shift of the dominating lasing modes in time is qualitatively discussed in terms of the carrier density induced change of the refractive index dispersion after the excitation laser pulse. This theory is supported by extending an existing model for the calculation of the carrier density dependent complex refractive index for different temperatures. This model coincides with the experimental observations and reliably describes the evolution of the refractive index after the excitation laser pulse.
我们使用时间分辨微光致发光技术报告了高质量 ZnO 纳米线的时间激光动力学。激光特性和相应衰减常数的温度依赖性表明，在考虑的温度范围内（从 10 K 到 300 K），形成电子-空穴等离子体是基础的增益机制。我们发现，与温度相关的发射起始时间 ([Formula: see text]) 强烈依赖于激发功率，并且在激光模式下变得最小，值低于 5 ps。此外，根据激发激光脉冲后折射率色散的载流子密度诱导变化，定性地讨论了观察到的主导激光模式的时间红移。该理论通过扩展现有的模型得到了支持，该模型用于计算不同温度下载流子密度相关的复折射率。该模型与实验观察结果吻合良好，能够可靠地描述激发激光脉冲后折射率的演变。
