ABSTRACT
This chapter reviews the effects that hydrogen incorporation pro-
duces on the electronic properties of dilute nitrides, as determined
by optical spectroscopy experiments. In the first instance, H brings
the band-gap energy of Ga(AsN) and related materials back to that
of the N-free host material. This dramatic finding is due to the
electronic passivation of N atoms by H atoms following the formation of specific N-H complexes. These complexes can be progressively
and controllably deactivated by either thermal, electron, or optical
treatments. Nitrogen passivation involves the entire band structure
of dilute nitrides and causes a tunable variation of the transport
(electron mass) and spin (electron gyromagnetic factor) properties.
The application of magnetic fields and hydrostatic pressures
combined with the effects of hydrogenation permits to unveil
an electronic hierarchy between different aggregates of N atoms
(N clusters [NCs]) that contribute to a different extent to determine
the puzzling compositional dependence of the physical properties of
these fascinating materials.
