Nitrogen incorporation into GaAsN and InGaAsN layers grown by liquid-phase epitaxy



This paper presents the comparison of nitrogen incorporation in GaAsN and InGaAsN layers grown on GaAs substrate from Ga- and In-rich solution, respectively, by liquid-phase epitaxy. Polycrystalline GaN has been used as a source of nitrogen in two cases. The initial epitaxy temperature has been varied in the temperature range 600-550 °C. Nitrogen content in Ga1-xAsNx grown layers has been determined to be in the range 0.1-0.5%. Higher nitrogen incorporation efficiency has been found for quaternary InGaAsN layers grown under carefully chosen lattice matched conditions. The incorporation of nitrogen into GaAsN and InGaAsN layers has been study by vibrational mode absorption spectroscopy. Nitrogen-induced vibration mode near 472 cm-1 has been registered in GaAsN samples. Preferential In-N bonds and the formation of N-centred In3Ga1 clusters have been identified for lattice matched to GaAs epitaxial InGaAsN layers. Electrical properties of the samples have been characterized by temperature-dependent Hall effect measurements. Nominally undoped GaAsN and InGaAsN grown layers are n-type with Hall concentration about one order of magnitude higher in comparison to layers not containing nitrogen. Thermally activated increase in the free carrier concentration at temperatures higher than 150 K is observed which indicates the presence of N-related deep donor levels below dilute nitride conduction band edge. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)