| GaInNAs grown on GaAs has recently been found to optically emit at wavelengths longer than previously thought possible with material grown epitaxially on GaAs substrates. Dilute-nitride GaInNAs alloys have quickly become an excellent candidate for low cost 1.3–1.55 μm vertical cavity surface emitting lasers (VCSELs) and high power edge emitting lasers in the past few years. Nitride-arsenide alloys were grown by solid source molecular beam epitaxy (MBE) using a N radio frequency (RF) plasma cell. The nitride-arsenide based crystal is grown under metastable conditions with low substrate temperatures and a highly reactive N radical plasma source. However, defects generated during this non-equilibrium growth are a source for non-radiative recombination and diminished photoluminescence (PL). By rapid thermal annealing (RTA) the material after growth, defects are removed from the crystal and the material quality of the GaInNAs films improves significantly. By measuring structural changes that occur during anneal, new insight has been made into the mechanisms which cause the optoelectronic properties to improve.; In an effort to further enhance crystal quality, Sb present during GaInNAs growth is thought to act as a surfactant to maintain surface planarity, and phase coherence, resulting in increased PL efficiency. With the addition of Sb, we have observed both a sharp intensity increase in samples with a high In concentration and a bandgap past 1.3 μm. Increasing the In or N content in materials with PL over 1.3 μm normally drops optical intensity; however, using Sb, we can maintain high PL efficiency out to 1.6 μm. Since both In and Sb in GaAs add compressive stress and the solubility of N in GaAs is limited, there is a need for GaNAs tensile strain compensating barriers for applications in multiple quantum well, high-intensity devices. With the development of GaInNAsSb alloys and strain compensated barriers, even longer wavelengths are possible on GaAs, greatly strengthening the dilute-nitride system as the technology of the future for long wavelength optoelectronic devices. |
