Nonlinear Dependence of N Incorporation on In Content in GaInNAs

Ga_1-xIn_xN_yAs_1-y with a few percent In and N has recently been demonstrated as a 1 eV material lattice-matched to GaAs. Similarly, it is expected that for Ga_0.5-xIn_0.5+xN_yAs_1-y, which is lattice-matched to InP, band gaps from ∼ 0.7-0.3 eV should be achievable if a few percent N could be incorporated. Here, we compare the growth of GaInNAs/InP with GaInNAs/GaAs. Epilayers of both alloy compositions were grown under comparable conditions by metal-organic vapor-phase epitaxy (MOVPE) with dimethylhydrazine. For GaInNAs/GaAs, nitrogen concentrations as high as 3% were measured, with corresponding bandgaps down to 0.96 eV. In contrast, for GaInNAs/InP, secondary ion mass spectroscopy (SIMS) measurements show a N concentration at least 100 times smaller in GaInNAs/InP than in GaInNAs/GaAs at comparable growth conditions, and, consistent with this observation, no bandgap depression is seen. Thus, N incorporation in GaInNAs falls off superlinearly with In concentration. Possible reasons for this are discussed.