Optical characterisation of self organized InAs/GaAs quantum dots grown by MBE

In this report we have investigated the optical characterisation of 2ML InAs/GaAs sheet grown by molecular beam epitaxy on (001) substrates. In particular we have studied the excitation energy dependence of PL spectra. The results allow us to resolve the emission from quantum dots (QDs) and that from the copper (Cu) centre in the GaAs substrate. A fast red shift of PL energy and an anomalous behaviour of linewidth with increasing temperature were observed and attributed to the tunnelling process between nearby QDs and electron–phonon scattering process.