CdSeS量子点的光吸收谱亚结构和光致发光激发谱分析

用光致发光激发(PLE)谱分析吸收谱的亚结构。实验样品是共熔法制备的CdSeS量子点玻璃，量子点的生长时间分别为2h和4h，高分辨透射电子显微镜(HRTEM)分析得到样品中量子点的平均直径分别为3．6nm和3．8nm。在室温下对样品进行了光吸收谱和光致发光激发谱研究。光吸收谱显示了量子尺寸效应，光致发光激发谱中低能端有两个明显的峰。考虑价带简并以及电子与空穴之间的相互作用，通过理论分析和数值计算，得到1S3/2-1Se和2S3/2-1Se的跃迁能量及其随量子点半径的变化，由此确认光致发光激发谱中的两个峰分别为1S3/2-1Se和2S3/2-1Se跃迁。

Photoluminescence Excitation Spectra and Absorption Spectra Analysis of CdSeS Quantum Dots

The sub-structure in absorption spectrum was analyzed by means of photoluminescence excitation (PLE) spectra. The glass samples of CdSeS quantum dots were prepared by co-melting and analyzed by means of high resolution transmission electron microscopy (HRTEM), the annealing time was 2 h and 4 h respectively, the quantum dots' diameter was 3.6 and 3.8 nm respectively. Absorption spectra and photoluminescence excitation spectra were measured at room temperature. The absorption spectra showed quantum size-dependent effects. Two peaks were observed in photoluminescence excitation spectra. The valence band degeneracy and the interaction between electrons and holes were taken into account, the energies of 1S3/2-1Se and 2S3/2-1Se transitions versus quantum dots' radii were obtained by theoretical analysis and numerical calculation. The two peaks in photoluminescence excitation spectra are assigned to 1S3/2-1Se and 2S3/2-1Se transitions, respectively.