Time-resolved photoluminescence studies of InGaN/GaN multiple quantum wells
J. Allègre, P. Lefebvre, S. Juillaguet, W. Knap, J. Camassel
Groupe d'Etude des Semiconducteurs, GES-CNRS
Q. Chen, M. A. Khan
APA Optics Inc.
This article was received on Tuesday, June 10, 1997 and
accepted on Monday, September 15, 1997. Abstract
We report both cw and time resolved optical investigations performed
on an InGaN/GaN multiple quantum well grown by MOVPE on <0001>-oriented
sapphire substrate. At low temperature we find a strong "blue" luminescence
band, of which energy position corresponds well with the wavelength of
stimulated emission when excited with a nitrogen laser. We show that this PL
band appears systematically red-shifted with respect to the QWs features, which
supports a standard picture of fluctuations of the indium composition. Coming
to the time-resolved data, we find at low temperature at least two "blue" band
components which are both associated with long decay times (up to 4-5 ns at
8K). The decay time is temperature dependent and, when rising the temperature,
the recombination rate increases. At room temperature, we reach typical values
in the range ~100 to 500 ps.
