Ultrafast Tunneling Spectroscopy of Semiconductor Superlattices

利用布居混合和时间相关单光子计算技术研究了GaAs-Al_ Ga_ As量子威尔斯中光生载流子在电场中的隧穿（垂直输运）和弛豫（激子形成）的竞争<0.29><0.71>.其次，<1-x>利用光致发光和吸收饱和技术研究了Al_xGa_ As-AlAs三元合金多量子阱结构在两个r-X交叉点附近的光学性质.最后，首次测量了交错排列Al_<0.34>Ga_<0.66>As-AlAs三元合金多量子阱结构中光生电子的层间r-X散射率.利用飞秒泵浦-探测光谱直接探测了散射过程。

The competition bewteen tunneling (vertical transport) and relaxation (exciton formation) of photo-generated carriers in GaAs-Al_<0.29>Ga_<0.71>As quantum wells in an electric field has been studied by using population mixing and time-correlated single photon conuting techniques.Secondary, we have studied the optical properties of Al_xGa_<1-x>As-AlAs ternary alloy multi-quantum-well structures around two r-X crossovers by means of photoluminescence and absorption saturation.Finally, the interlayer r-X scattering rate of photoexcited electrons was measured in staggered-alignment Al_<0.34>Ga_<0.66>As-AlAs ternary alloy multi-quantum-well structures for the first time. The scattering process was directly probed by the femtosecond pump-and probe spectroscopy.