Dilute-Nitride Type-II Quantum Well Lasers Grown by MOCVD

Abstract : One challenging goal remaining for GaAs-based InGaAsN QW lasers is to extend the emission wavelength beyond 1.3 m, while maintaining optical material quality for the realization of longer wavelength and high performance. Higher N-content leads to increased nonradiative monomolecular recombination, thus high performance at 1.55 m has not been achieved to date. Recently, we proposed a novel approach for realizing GaAs-based diode lasers with emission wavelengths beyond =1500 nm. This approach utilizes the type-II band alignment between InGaAsN and GaAsSb. The PL emission wavelengths of previous InGaAs-GaAsSb type-II QW lasers, were generally limited to 1200-1400 nm, mainly due to strain limitations and the larger bandgap of InGaAs. We have performed design studies using the 10-band k.p method to determine the compositional dependances of the optical matrix clement and emission wavelength corresponding to the type-II transition. Increasing the In and Sb contents both extend the emission wavelength, due to reduced bandgap for the corresponding layers. The dilute-nitride type-II laser structures reported here were grown by metalorganic chemical vapor deposition (MOCVD), at an active region growth temperature of 530 deg. C and reactor pressure of 100 mbar. 3-stage In0.37Ga0.62As0.98N0.02-GaAs0.7Sb0.3 "W" QW laser were fabricated and characterized.