Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 100: Metamorphic structures: Bringing together incompatible materials II (Focus session with DF)
HL 100.2: Talk
Thursday, April 3, 2014, 15:30–15:45, POT 251
Optical and structural characterization of an InGaN SQW embedded between quaternary InAlGaN barriers of varying In-concentration — •Christopher Karbaum1, Frank Bertram1, Marcus Müller1, Peter Veit1, Jürgen Christen1, Jürgen Bläsing1, Alois Krost1, Martin Feneberg1, Rüdiger Goldhahn1, Jan Wagner2, Michael Jetter2, and Peter Michler2 — 1Institute of Experimental Physics, OvGUniversity Magdeburg, Germany — 2IHFG, University Stuttgart, Germany
The change of the optical and structural properties of an InGaN SQW within InAlGaN barriers have been investigated using time resolved SEM-CL and STEM-CL spectroscopy at liquid helium temperature, PL, and HRXRD. The set of samples was grown on an optimized 1 µ m thick GaN:Si buffer ontop of a c-oriented sapphire substrate. Subsequently, an InGaN SQW was embedded between InAlGaN barrier layers. The In gas flow during the pulsed MOVPE growth of these barriers was varied from 3 sccm up to 50 sccm. PL-spectra are dominated by the bound exciton emission of GaN (355 nm), a DAP at about 380 nm, the broad emission band from the InGaN SQW between 450 nm and 500 nm and the quaternary InAlGaN barrier emission. The fundamental idea behind the variation of the In-flux during growth is to achieve polarization matched conditions to decrease the QCSE of the InGaN SQW emission. For higher In-fluxes the InGaN emission undergoes a blueshift (150 meV) accompanied by a decrease of initial lifetime from 18 ns down to 5 ns. The temperature dependence of the luminescence and the recombination kinetics will be discussed.