ENERGY-LEVELS IN SELF-ASSEMBLED INAS GAAS QUANTUM DOTS ABOVE THE PRESSURE-INDUCED GAMMA-X CROSSOVER/

Low-temperature photoluminescence (PL) studies of InAs self-assembled quantum dots (SAQD's) embedded in a GaAs matrix have been performed un der hydrostatic pressure P up to 70 kbar. A strong blueshift of the PL line from the SAQD's with P up to 53 kbar changes to a relatively sma ll redshift at higher P. This is the fingerprint of a T-X crossover. A bove the crossover pressure, we find experimental evidence for type-II band alignment in the InAs SAQD/GaAs heterostructure system. This giv es a reference point that allows us to determine independently the ene rgies of the electron and hole levels in the QD.