Stimulated emission properties of AlGaN‐based multiple quantum wells with an emission wavelength of about 280 nm are studied by photoluminescence excitation (PLE) spectroscopy. The excitation power density dependence of the PLE spectra is evaluated at excitation energies from 4.4788 to 4.6293 eV, which allows the spontaneous and stimulated emission PLE spectra to be obtained. A clear peak is observed in the PLE spectrum for spontaneous emission, indicating that the spontaneous emission is due to the excitonic optical transition. A clear peak is also observed in the PLE spectrum for stimulated emission, suggesting that excitons are involved in the stimulated emission process. Furthermore, the threshold excitation power density for stimulated emission is analyzed as a function of the excitation energy and the threshold excitation power density depends on the excitation energy. The excitation energy at which the threshold excitation power density is minimized agrees with the peak of the stimulated emission PLE spectrum. This observation directly indicates that excitons are important in optical gain formation.

中文翻译：

---

发射波长约为 280 nm 的 AlGaN 基多量子阱受激发射的光致发光激发光谱

通过光致发光激发（PLE）光谱研究了发射波长约为 280 nm 的 AlGaN 基多量子阱的受激发射特性。 PLE 光谱的激发功率密度依赖性在 4.4788 至 4.6293 eV 的激发能量下进行评估，从而获得自发和受激发射 PLE 光谱。在自发发射的 PLE 光谱中观察到清晰的峰，表明自发发射是由于激子光学跃迁引起的。在受激发射的 PLE 光谱中还观察到了清晰的峰，表明激子参与了受激发射过程。此外，受激发射的阈值激发功率密度被分析为激发能量的函数，并且阈值激发功率密度取决于激发能量。阈值激发功率密度最小化时的激发能量与受激发射 PLE 光谱的峰值一致。这一观察结果直接表明激子在光学增益形成中很重要。