Continuous-wave photoluminescence excitation spectra of multiple narrow-stepped quantum wells: Evidence for saturation of interface traps

Abstract

Continuous-wave photoluminescence excitation spectra of multiple narrow-stepped quantum wells at room temperature have been measured for the first time. It has been observed that photoluminescence intensity increases stronger than proportionally to the square of the laser intensity. This phenomenon can be attributed to the radiative recombination between free carriers in parallel with the dominant nonradiative recombination on the saturable interface traps. Intensity-dependent trapping efficiency and ratio between electron and hole nonradiative decay times, and the ratio between trapping and nonradiative recombination rates have been derived from the experiment.