Xu Xingsheng, Li Xingyun
State Key Laboratory of Integration Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
Sci Rep. 2015 May 19;5:9760. doi: 10.1038/srep09760.
We investigate the photoluminescence (PL) spectra and the time-resolved PL decay process from colloidal quantum dots on SiN/SiO2 wet etched via BOE (HF:NH4F:H2O). The spectrum displays multi-peak shapes that vary with irradiation time. The evolution of the spectral peaks with irradiation time and collection angle demonstrates that the strong coupling of the charged-exciton emission to the leaky modes of the SiN/SiO2 slab waveguide predominantly produces short-wavelength spectral peaks, resulting in multi-peak spectra. We conclude that BOE etching enhances the charged-exciton emission efficiency and its contribution to the total emission compared with the unetched case. BOE etching smoothes the electron confinement potential, thus decreasing the Auger recombination rate. Therefore, the charged-exciton emission efficiency is high, and the charged-exciton-polariton emission can be further enhanced through strong coupling to the leaky mode of the slab waveguide.
我们研究了通过BOE（氢氟酸：氟化铵：水）湿法蚀刻的SiN/SiO₂上胶体量子点的光致发光（PL）光谱和时间分辨PL衰减过程。该光谱呈现出随辐照时间变化的多峰形状。光谱峰随辐照时间和收集角度的演变表明，带电激子发射与SiN/SiO₂平板波导的泄漏模式的强耦合主要产生短波长光谱峰，从而导致多峰光谱。我们得出结论，与未蚀刻的情况相比，BOE蚀刻提高了带电激子发射效率及其对总发射的贡献。BOE蚀刻使电子限制势平滑，从而降低了俄歇复合率。因此，带电激子发射效率很高，并且通过与平板波导的泄漏模式的强耦合可以进一步增强带电激子极化激元发射。
