Deep impurity transitions involving cation vacancies and complexes in AlGaN alloys Available to Purchase

Deep ultraviolet (UV) photoluminescence (PL) spectroscopy has been employed to study deep impurity transitions in $AlxGa1−xN$ $(0⩽x⩽1)$ epilayers. Two groups of deep impurity transitions were observed, which are assigned to the recombination between shallow donors and two different deep level acceptors involving cation vacancies $(Vcation)$ and $Vcation$ complexes in $AlxGa1−xN$ alloys. These acceptor levels are pinned to two different energy levels common to $AlxGa1−xN$ alloys $(0⩽x⩽1)$⁠. The deep impurity transitions related with $Vcation$ complexes were observed in $AlxGa1−xN$ alloys between $x=0$ and 1, while those related with $Vcation$ were only observed in $AlxGa1−xN$ alloys between $x=0.58$ and 1. This points out to the fact that the formation of $Vcation$ is more favorable in Al-rich AlGaN alloys, while $Vcation$ complexes can be formed in the whole range of $x$ between 0 and 1. The implications of our findings to the UV optoelectronic devices using AlGaN alloys are also discussed.