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GaInN; lifetimes; fluctuations; time-resolved photoluminescence
Abstract:
We present results of temperature-dependent, time-resolved
photoluminescence (PL) measurements on a set of Ga1-xInxN (x
congruent to 0.08) layers grown at the same conditions on three
different substrates: bulk (high pressure grown) GaN, SiC and
Al2O3. At 9 K, the maximum of the PL occurs at about 3.1 eV.
The linewidths are 48, 80 and 90 meV for the layers grown on
GaN, Al2O3 and SiC, respectively. The smallest width suggests
the highest homogeneity of the GaInN/GaN. The PL lifetimes
(about 0.8 ns) and intensities are similar in all three
samples. The spectral diffusion of the PL (shift of the PL peak
energy with time) is thermally activated. The highest shift
(DeltaE = 90 meV) and an activation energy E-a = 80 meV are
observed in the GalnN/SiC sample, the lowest (DeltaE < 3 meV)
in the GaInN/GaN sample, The smallest DeltaE (interpreted as a
conduction and valence band fluctuation amplitude) found in the
layer grown on GaN is due to the low dislocation concentration
resulting from the good lattice matching. (C) 2002 Elsevier
Science B.V. All rights reserved.
