Evidence Of Type-I Direct Recombination In Inp/Gap Quantum Dots Via Magnetoluminescence

Photoluminescence from InP quantum dots within a GaP matrix is investigated as a function of magnetic field. By fitting the magnetoluminescence data to the energy states of the electrons and holes confined in quantum dots in a perpendicular magnetic field, the electron-hole reduced effective mass is determined to be 0.094m(0). The diamagnetic shift in the luminescence peak gives an average exciton radius of about 5 nm, smaller than the dot radius. These results indicate that the recombining electrons are primarily composed of states originating from the InP Gamma valley although the conduction band discontinuity between the InP and the GaP barrier is expected to be very small or even negative. (C) 2009 American Institute of Physics. [doi:10.1063/1.3246161]