We report the growth and characterization of quaternary AlGaInN. A combinat
ion of photoluminescence (PL), high-resolution X-ray diffraction (XRD), and
Rutherford backscattering spectrometry (RBS) characterizations enables us
to explore the contours of constant-PL peak energy and lattice parameter as
functions of the quaternary compositions. The observation of room temperat
ure PL emission at 351 nm (with 20%Al and S%In) renders initial evidence th
at the quaternary could be used to provide confinement for GaInN (and possi
bly GaN). AlGaInN/GaInN multiple quantum wells (MQWs) heterostructures have
been grown; both XRD and PL measurement suggest the possibility of incorpo
rating this quaternary into optoelectronic devices.