Electron coupling in InGaAs/GaAs quantum dot-pairs fabricated with InP island stressors

Coupled quantum dot (QD)-pairs were fabricated by stressing the near-surface InGaAs/GaAs coupled quantum wells (QWs) with self-assembled InP islands. The coupling strength in the dot-pair was studied by varying the barrier layer width separating the two dots and the indium composition in the lower dot. Strong coupling was observed at a barrier less than 4 nm. Anti-bonding of the two ground states as well as all the bonding states were observed by state filling in the photoluminescence spectra. By tuning the indium composition in the lower QW to adjust the lower QD state energies before coupling relative to those in the upper QD, crossing of the bonding and anti-bonding states is achieved