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采用时间分辨抽运-探测透射光谱,研究了不同波长和不同激发流密度下半金属Sb薄膜的超快电子动力学过程.透射变化率的时间延迟扫描曲线显示在延迟零点附近出现强的振荡,正的吸收饱和峰在亚皮秒时间内衰减为负的吸收增强峰.之后,负的吸收增强峰在数皮秒时间内甚至再次演变为吸收饱和.正饱和峰和负吸收峰幅度正比于激发流密度和光波长.对这些现象进行了分析,引入“缺陷”态模型及考虑“缺陷”态对光激发电子的快速俘获和逐渐释放,能够合理、半定量地解释实验观察到的所有现象.
The time-resolved pumping-probe transmission spectroscopy was used to investigate the ultrafast electron kinetics of semi-metallic Sb thin films with different wavelengths and different excitation densities. The time-delay scanning curves of the rate of change of transmission show that there is strong oscillation around the zero- The positive absorption peak decays to a negative absorption enhancement peak in sub-picosecond time, after which the negative absorption enhancement peak even changes to absorption saturation again in a few picoseconds. The amplitude of positive and negative absorption peaks is proportional to the excitation Flow density and optical wavelength.These phenomena were analyzed and the “trapped” state model and the “defect” state were introduced to capture and release the photoexcited electrons rapidly and reasonably and semiquantitatively to explain the experimentally observed All phenomena.