Absorption and emission of (In,Ga)N/GaN quantum wells grown by molecular beam epitaxy

Thermally detected optical absorption (TDOA) and photoluminescence experime nts are carried out on In0.16Ga0.84N/GaN multi-quantum wells (MQWs) grown b y molecular beam epitaxy on (0001) sapphire substrates. A model proposed to adjust the TDOA line shape, allows to deduce the band-edge energies, the a bsorption coefficients and the broadening parameters of the (In,Ga)N MQWs f or different thicknesses. The Fabry-Perot oscillations, which structure the TDOA spectra, are considered in this modelling to accurately account for t he experimental data. The emission, which covers the whole visible spectrum at room temperature, is achieved by varying the thickness from 1.5 to 5 nm . A very large Stokes shift between the emission and absorption energies is deduced at low temperature, for the (In,Ga)N MQWs.