Localized excitonic recombination in undoped Ga N quantum well nano structures

The paper is mainly based on experimental investigations by using a combination of photoluminescence and time resolved photo-luminescence techniques. A pronounced S-shapetemperature dependence is observed for emission peak of all samples implying a recombination from localized states at low temperature. The time-resolved photoluminescence spectra of the 3 nm well multiple quantum wells reveal that the spectral peak position shifts toward lower energies as the decay time increases and becomes red-shifted at longer decay times. By comparing experimental and calculation results, we have obtained a low limit of the piezoelectric field strength to be about 48 MV/m in the 3 nm well Ga N/Al0.07Ga0.93N multiple quantum wells.