N. Grandjean et al., Enhanced luminescence efficiency due to exciton localization in self-assembled InGaN/GaN quantum dots, SOL ST COMM, 113(9), 2000, pp. 495-498
GaN/InGaN heterostructures were grown by molecular beam epitaxy on sapphire
(0001). The photoluminescence (PL) of InGaN/GaN quantum wells rapidly vani
shes when the temperature increases from 10 to 100 K and is totally quenche
d above 150 K. This is the consequence of the high density of dislocations
(10(9)-10(10) cm(-2)) inherent to nitride layers grown on sapphire. InGaN/G
aN quantum dots (QDs) have been fabricated by takings advantage of the Stra
nski-Krastanov growth mode. In this case, the PL intensity is still intense
at room temperature. This is due to the three-dimensional localization of
carriers in the dots which hinders their migration towards non-radiative ce
nters. The radiative efficiency of InGaN QDs was further improved using an
AlGaN cladding layer. The PL integrated intensity reduces by less than one
order of magnitude between 10 and 300 K. (C) 2000 Elsevier Science Ltd. All
rights reserved.