Uh. Lee et al., Visible photoluminescence from self-assembled InAs quantum dots embedded in AlAs cladding layers, APPL PHYS L, 74(11), 1999, pp. 1597-1599
Photoluminescence (PL) from InAs self-assembled quantum dots (QD) embedded
in the AlAs matrix was strong and clean around 700 nm. PL efficiency remain
ed quite high at room temperature compared to other QD systems embedded in
GaAs cladding layers. Transmission electron microscope pictures from the st
ructure showed a clear formation of relatively small and coherently straine
d InAs QD. The observed blueshift with accompanying broadening of PL spectr
a with the increase of excitation power is interpreted in terms of local ca
rrier tunneling in a dense QD system. The PL peak redshift with the increas
e of temperature was very large, as much as 228 meV. The anomalous shift is
interpreted as due to activation-energy differences between dots of differ
ent sizes. (C) 1999 American Institute of Physics. [S0003-6951(99)02811-9].