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The realization of long-wavelength (lambda <= 2.3 µm) Ga(1-x)In(x)As(1-y)N(y) quantum wells on InP by molecular-beam epitaxy
Realisierung von langwelligen GaInAsN Quantenfilmen auf InP mittels Molekular-Strahl Epitaxie
The epitaxial growth and characterization of dilute Ga(1-x)In(x)As(1-y)N(y) films and quantum wells are presented. Starting with the epitaxy on GaAs, recent results on the local bonding of nitrogen in Ga(1-x)In(x)As(1-y)N(y) are reviewed, revealing that bonding of nitrogen is controlled by an interplay between bond cohesive energy and reduction of local strain. Thus, III-N bonding in Ga(1-x)In(x)As(1-y)N(y) can be changed from Ga-N to In-N by post-growth thermal annealing. Nitrogen loss due to the annealing process is not observed. We then adopted this concept for the epitaxy on InP substrates, which is equivalent to a drastic increase in indium content of the Ga(1-x)In(x)As(1-y)N(y) system and thus an extension to longer wavelength. The low-energy shift of quaternary pseudomorphically strained Ga(0.4)In(0.6)As(1-y)N(y) double quantum wells upon nitrogen incorporation is reported. The deterioration of the photoluminescence characteristics in terms of reduced peak intensity andincreased linewidth with increasing nitrogen incorporation can be partially compensated by rapid thermal annealing, which is accompanied by a blueshift with respect to the as-grown samples. Within the resolution limits of our secondary ion mass spectrometry experiments, no annealing-induced loss of nitrogen was observed even for the high indium content Ga(1-x)In(x)As(1-y)N(y) quantum well structures. The results of indium-rich highly strained Ga(0.22)In(0.78)As(0.99)N(0.01) quantum wells on InP substrate are reported, showing room temperature photoluminescence at wavelengths up to 2.3 µm. We finally conclude with the demonstration of multi quantum well lasers emitting at wavelengths beyond 2 µm.