QUANTUM DOT MOLECULES IN QUANTUM WELLS FOR PHOTOVOLTAIC APPLICATIONS

High density InAs quantum dot molecules (QDMs) inserted in GaAs/AlGaAs quantum well system is proposed as an active part of high efficiency, high performance solar cells. The QDM-in-QW structure is grown and characterized by photoluminescence (PL) measurements. Quantum confinement of carriers in InAs QDMs gives PL spectrum which peaks at 1055 nm and with FWHM of 41.4 meV. Red emission of PL peak at 636 nm with FWHM of 15.2 meV is also observed and this is originated from the AlGaAs/GaAs quantum well. High growth temperature of AlGaAs at 600°C gives an annealing effect to improve dot homogeneity of InAs QDMs which are grown at a lower temperature of 470°C.