The splitting and shifting of eigen-energy levels of coupled binary quantum dots was theoretically studied. The amount of splitting as a function of applied electric field strength, in particular, was investigated. The eigen-energy of the system was calculated from the time-independent Schrodinger equation using a finite-difference method. It was found that a larger electric field leads to a larger amount of eigen-energy splitting. Since the degree of linear polarization is related to the amount of splitting of the eigen-energies, we can expect that the binary quantum dots should exhibit a stronger degree of linear polarization with increasing applied electric field.

Optical properties of InAs binary quantum dot (bi-QD) molecules grown on the (001) GaAs substrate were measured by means of temperature- and excitation-power-dependent photoluminescence (PL) spectroscopy. It was observed that the shape and peak position of the PL spectra changed with the temperature and with the excitation power. It was also found that the linear polarization degree of the bi-QD PL signal changed with temperature. The temperature-dependent PL described that the linear polarization degree of bi-QDs is closely related to the carrier dynamics.