Optical properties of thick GaInAs(Sb)N layers grown by liquid-phase epitaxy

[摘要] We present an experimental and theoretical study of GaInAs(Sb)N layers with thickness around 2 μm, grown by liquid-phase epitaxy (LPE) on n-type GaAs substrates. The samples are studied by surface photovoltage (SPV) spectroscopy and by photoluminescence spectroscopy. A theoretical model for the band structure of Sb-containing dilute nitrides is developed within the semi-empirical tight-binding approach in the sp3d5s∗sNparameterisation and is used to calculate the electronic structure for different alloy compositions. The SPV spectra measured at room temperature clearly show a red shift of the absorption edge with respect to the absorption of the GaAs substrate. The shifts are in agreement with theoretical calculations results obtained for In, Sb and N concentrations corresponding to the experimentally determined ones. Photoluminescence measurements performed at 300K and 2 K show a smaller red shift of the emission energy with respect to GaAs as compared to the SPV results. The differences are explained by a tail of slow defect states below the conduction band edge, which are probed by SPV, but are less active in the PL experiment.

[发布机构] Faculty of Physics, Sofia University, 5, J.Bourchier blvd., Sofia; 1164, Bulgaria^1;Central Laboratory of Applied Physics, 59 St. Petersburg blvd, Plovdiv; 4000, Bulgaria^2;Department of Physics, Imperial College London, London, United Kingdom^3;Department of Physics, University of Ottawa, Ottawa; ON; K1N 6N5, Canada^4;Linköping University, Department of Physics, Chemistry and Biology, Linköping; 581 83, Sweden^5

[关键词] Alloy compositions;Conduction band edge;Emission energies;Photoluminescence measurements;Surface photovoltage spectroscopy;Theoretical calculations;Theoretical modeling;Theoretical study