Y. Kim et al., Ripening suppression and large photoluminescence blueshift in aligned InGaAs quantum dots on a vicinal, (100) GaAs substrate, J APPL PHYS, 85(4), 1999, pp. 2140-2145
We observe ripening suppression in aligned InGaAs quantum dots (QDs) along
multiatomic steps on a vicinal (100) GaAs substrate. By varying the growth
interruption times, a study of QD morphologies by atomic force microscope r
eveals a clear Ostwald ripening suppression effect on QD formation. On the
other hand, we observe a regular ripening for InGaAs QDs on an exact (100)
substrate. In addition, n-QD chains aligned along multiatomic steps are obs
erved. An inhomogeneously broadened photoluminescence (PL) spectrum with la
rger spectral width is obtained for a QD ensemble on a vicinal (100) substr
ate as compared to those on an exact (100) substrate although statistical a
nalyses of QD size distributions show similar size dispersions. The spectra
l broadening is attributed to the lateral quantum coupling of aligned n-QD
chains. PL spectra for QDs on vicinal (100) substrates show a larger rate o
f blueshift with increasing interruption times, which is interpreted as a l
ack of the PL compensation effect by size enlargement of the QDs during gro
wth interruption. Thus the result supports the ripening suppression effect
which is observed in the morphology study. (C) 1999 American Institute of P
hysics. [S0021-8979(99)10503-6].