Anti-Stokes photoluminescence between Inx(Al0.17Ga0.83)1-xAs/ Al0.17Ga0.83As quantum wells with different x values

摘要

Anti-Stokes photoluminescence (AS-PL) has been investigated in a step-gradedInx(Al0.17Ga0.83)1-xAs/Al0.17Ga0.83As quantum well (QW) system consisting of five QWs with different xvalues. When a low-energy heavy-hole (1s) exciton state in a particular well is resonantly photoexcited, thehigh-energy heavy-hole (1s) exciton in the nearest-neighbor well shows a stronger AS-PL intensity than otherQWs beyond the nearest-neighbor QW. The AS-PL intensity of (1s) excitons observed in each well shows adrastic position dependence on where carriers are resonantly photoexcited, indicating energy transferprocesses with a spatial position dependence. These results mean that the up-conversion phenomenaresponsible for generating high-energy carriers can be influenced by transfer and capture processes into thehigh-energy exciton state in addition to nonlinear excitation mechanisms.