The realization of long-wavelength(λ ≤2.3 µm)Ga1−xInxAs1−yNy quantum wells on InP by molecular-beam epitaxy

Abstract

The epitaxial growth and characterization of diluteGa1−xInxAs1−yNy films and quantum wells are presented. Starting with the epitaxyon GaAs, recent results on the local bonding of nitrogen inGa1−xInxAs1−yNy are reviewed, revealing that bonding of nitrogen is controlled by an interplaybetween bond cohesive energy and reduction of local strain. Thus, III–N bonding inGa1−xInxAs1−yNy can be changed from Ga–N to In–N by post-growth thermal annealing. Nitrogen loss due tothe annealing process is not observed. We then adopted this concept for the epitaxy on InPsubstrates, which is equivalent to a drastic increase in indium content of theGa1−xInxAs1−yNy systemand thus an extension to longer wavelengths. The low-energy shift of quaternary pseudomorphicallystrained Ga0.4In0.6As1−yNy double quantum wells upon nitrogen incorporation is reported. The deterioration of thephotoluminescence characteristics in terms of reduced peak intensity and increasedlinewidth with increasing nitrogen incorporation can be partially compensated by rapidthermal annealing, which is accompanied by a blueshift with respect to the as-grownsamples. Within the resolution limits of our secondary ion mass spectrometry experiments,no annealing-induced loss of nitrogen was observed even for the high indium contentGa1−xInxAs1−yNy quantum well structures. The results on indium-rich highly strainedGa0.22In0.78As0.99N0.01 quantumwells on InP substrate are reported, showing room temperature photoluminescence at wavelengths up to2.3 µm. Wefinally conclude with the demonstration of multi quantum well lasers emitting at wavelengths beyond2 µm.