LONGITUDINAL TRANSPORT IN GA1-XALXAS P-N-JUNCTIONS INCORPORATING GAASQUANTUM-WELLS - HOT-ELECTRON LIGHT EMITTERS

Experimental results on hot-electron parallel transport in GaAs quantu m wells, situated in the n-side of the depletion region of a Ga1-xAlxA s p-n junction, are presented. In our structures hot electrons are the rmionically excited from the n-side of the junction into the quantum w ells in the depletion region, by the application of pulsed longitudina l electric fields. The accumulation of the electrons in the depletion region modifies the potential profile of the junction, resulting in a reduction of the potential barrier and the depletion width in the p-si de. Thus, hot holes are excited into the valence bands of the quantum wells via thermionic emission or tunnelling to recombine radiatively w ith the electrons. A simple modelling of the device is carried out by solving the Poisson and Schrodinger equations for the p-n junction inc orporating a single quantum well.The results of this modelling describ e the experimental observations very well. It is also shown that popul ation inversion in the junction can be achieved at high fields. The de vice is therefore a very efficient light emitter with the main advanta ges over the conventional laser diodes being: the emitted light is ind ependent of the polarity of the applied voltage; and only two point co ntacts are required, thus making it a very simple device to fabricate.