TEMPERATURE QUENCHING OF TUNABLE TUNNELING RECOMBINATION EMISSION IN ALXGA1-XAS N-I-P-I DOPING STRUCTURES

Competing emissions arising from e-h recombinations within the same la yer (spatial-direct) and across layers (spatial-indirect) in AlxGa1-xA s n-i-p-i doping structures have been studied using photoluminescence (PL). The emission from spatial-indirect transitions dominate at low t emperatures (<50K). The cross-over temperature, T-x, at which the spat ial-direct transition overtakes in intensity arising from spatial indi rect transition, is found to be dependent on intrinsic layer thickness and the doped layer concentrations but weakly dependent on the excita tion laser power density for values beyond 0.5 W cm(-2). The spatial-d irect transition is not observed when the intrinsic layer is not prese nt. The ratio of intensities between the spatial-direct to the spatial -indirect transitions is described by an exponential function which is in agreement with theoretical prediction. (C) 1997 Elsevier Science L td.