Enhancement of the direct optical transition in nanocrystallized GaAsN alloys

Changes in Optical Properties of GaAsN During Annealing

“…The observed LO 1 for the type B sample indicates a nitrogen content of about 1%, consistent with the PL emission. Annealing results in a Raman shift consistent with loss of nitrogen as suggested by many studies [9,12] while annealing at higher temperatures results in a shift suggesting nitrogen enrichment, suggestive of a 4% nitrogen content. Type A samples exhibited both a much smaller shift, but had the same trend - initial N-depletion followed by N-enrichment.…”

Reactively sputtered GaAsxN1−x thin films

“…The difference in the structures of GaAs and GaN and the large difference in the sizes of arsenic and nitrogen do not allow the formation of complete range of solid solution in this alloy. The smaller size of N allows its solubility in GaAs and extensive research has been reported on such alloys [3][4][5][6][7][8]. In comparison, owing to the larger size of As and consequent difficulty in the incorporation of As in GaN, very limited work has been reported on N-rich side of GaAs x N 1−x alloys, which have been mostly prepared by MOCVD and MBE [9,10].…”

Epitaxially grown GaAsN random laser

“…There could also be other sources of light scattering in this alloy system. Gwo et al, 16 for example, found evidence for nanocrystals embedded at the interface between GaAsN and GaAs, which they assumed were due to the segregation of GaN in this alloy. These obvious structural inhomogeneities could very well explain the efficient light scattering necessary for random lasing.…”

“…A number of previous studies have called attention to the inherent inhomogeneous structural properties of this group of alloys. 16,17 For example, optical absorption and Raman studies have suggested that alloy ordering may take place in these alloys, while other studies indicate the existence of nitrogen enriched GaAsN clusters due to the significant differences in atomic size and electronegativity between As and N. 16,17 In addition, for GaAsN layers with thickness above the critical layer thickness, strain relaxation occurs and misfit dislocations develop. 18 Although the exact value of the critical layer thickness is still a mater of controversy, our 500-nm-thick, 2.8% nitrogen containing layers are well above all estimates for the critical thickness for this alloy.…”