Spectroscopy of the interaction between nitrogen and hydrogen in ZnSe epitaxial layers

Abstract

We report on detailed optical-spectroscopy investigations of nitrogen-doped ZnSe epitaxial layers of various doping levels and N contents which have been exposed ex situ to a hydrogen/deuterium plasma. The influence of this treatment is studied through temperature-dependent photoluminescence and selective photoluminescence. The results are similar for all samples, irrespective of their doping properties. We show that the ${\mathrm{N}}_{\mathrm{Se}}$ acceptor is strongly passivated and that the deep compensating-donor disappears after plasma exposure. In addition, the nature of the main shallow compensating-donor is changed by the $H/D$ treatment. The shallow donor in ZnSe:N which we have previously identified as a N-related defect is suppressed while the usual residual impurities of ZnSe are uncovered. Our results directly demonstrate that all compensating donors in ZnSe:N material are N-related defects, and that N may participate to nonradiative recombination centers at heavy doping. Finally, this helps selecting a few models for the deep compensating-donor and further support the implication of N interstitials in carrier compensation in ZnSe:N.