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Optically active states in liquid phase epitaxy-grown ultra-dilute GaAsN are studied. The feature-rich low temperature photoluminescence spectrum has contributions from excitonic band states of the GaAsN alloy, and two types of defect states-localized and extended. The degree of delocalization for extended states both within the conduction and defect bands, characterized by the electron temperature, is found to be similar. The degree of localization in the defect band is analyzed by the strength of the phonon replicas. Stronger emission from these localized states is attributed to their giant oscillator strength. V

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Dilute GaAsN layers are grown by the liquid phase epitaxy technique from a GaAs + Ga + GaN melt with up to 2 mol% Li 3 N added to the same to act as a flux to promote nitrogen dissolution in Ga. X-ray diffraction study indicates a nitrogen content of 0.9 at.% in the material. 10 K photoluminescence measurements indicate a band gap reduction of 130 meV in the as-grown layers which increases to 150 meV after a high-temperature anneal. Energy dispersive x-ray measurements indicate incorporation of Li in the material and local vibrational modes related to both nitrogen and Li are observed through Raman spectroscopy. Furthermore, a photoluminescence peak at 1.33 eV is suggested to be due to Li.

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