Enhancement of photoluminescence quantum efficiency in semiconductor structures with reduced dimensionality

Abstract

We have investigated photoluminescence quantum efficiency (QE) in disordered semiconductor systems. The value of QE is shown to depend strongly on the ratio of the temperature to the energy spread of localized electron states. We found that the high recombination rate of nonradiative centers (killers) could be reduced by the low mobility of carriers. The consequence is an enhancement of QE which is ever more remarkable in 1d semiconductor structures. This result can be used as an explanation for the high QE of porous Si, which is represented as an example of a disordered quasi-one-dimensional structure.