RESONANT EXCITATION OF BOUND EXCITON LUMINESCENCE IN GaAs1-x Px ALLOYS

Abstract

Bound exciton luminescence in GaAs/sb>1-xPx alloys is sufficiently broadened by alloy disorder that little information can be gained about electronic energies and phonon couplings. By resonantly exciting narrow exciton components with a dye laser we have recovered sharp luminescence features like those in GaP. Detailed results are given for x=0.50 where broadening is greatest. Excitons bound to group VI donors show phonon coupling characteristic of an effective mass level at the X1 conduction band minimum, whereas nitrogen traps show phonon assistance characteristic of a deep level–stronger coupling to phonons throughout much of k-space and more zero phonon broadening. We identify phonons and verify zero-phonon luminescence lineshape for both cases.