Authors
Abstract
Recently, the quaternary InGaAsN alloy system has attracted a great deal of attention due to its potential application in devices such as next generation multi-junction solar cells and optoelectronic devices for example laser diodes for optical communications in IR region. In this paper, we have investigated the role of nitrogen on the improvement of optical efficiency in InGaNAs nanostructures by photoluminescence spectroscopy. These characterizations are because of variation of InGaNAs band structure due to existence of nitrogen, and could be explained by using band anticrossing model which is a result of interaction between the extended conduction band of the InGaAs matrix (EM) and the nitrogen-related localized level (EN). The band-gap of InGaNAs is very sensitive to the nitrogen content, so it has decreased by increasing of nitrogen content. Therefore accessibility to emission light wavelength at IR region is controllable. Moreover, nitrogen has created the potential fluctuations in the InGaNAs so it is the cause of trap centers that leads to localized excitons. Thus the probability of exciton recombination has increased and improved optical efficiency of these structures. But in other cases, nitrogen has made fluctuations especially in the common surface of the well and barrier in InGaNAs quantum structures so they increase non-radiative recombination.
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