Energy level of defects

In addition to the radiative processes, there are nonradiative processes in semiconductors because of imperfections that act as nonradiative centers. We should mention some defects as radiative recombination centers, which in a photoluminescence experiment can shed light on the energy levels of defect states. For a semiconductor containing nonradiative traps or recombination centers, in an experiment such as time-dependent PL, the decay in the integrated PL intensity versus temperature is related to the low-temperature integrated PL intensity as... 

First-principles calculations based on the density functional theory (DFT) within the local density approximation plus the Hubbard model (LDA + U) can predict not only the probability of the defect formation but also the energy levels of defects in... 

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