We report on detailed optical-spectroscopy investigations of nitrogen-doped
ZnSe epitaxial layers of various doping levels and N contents which have b
een exposed ex situ to a hydrogen/deuterium plasma. The influence of this t
reatment is studied through temperature-dependent photoluminescence and sel
ective photoluminescence. The results are similar for all samples, irrespec
tive of their doping properties. We show that the Ns, acceptor is strongly
passivated and that the deep compensating-donor disappears after plasma exp
osure. In addition, the nature of the main shallow compensating-donor is ch
anged by the HID treatment. The shallow donor in ZnSe:N which we have previ
ously identified as a N-related defect is suppressed while the usual residu
al 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. Fi
nally, this helps selecting a few models for the deep compensating-donor an
d further support the implication of N interstitials in carrier compensatio
n in ZnSe:N.