Intensity and spatial modulation of spontaneous emission in GaAs by field aperture selecting transport

A potential technique for modulating the light emission resulting from excess minority carrier recombination in a semiconductor device is introduced. This process utilizes an electric field to transport a packet of minority carriers past an optical output aperture defined on the surface of the semiconductor. A short burst of light is allowed to escape through the surface of the device as the packet drifts past the opening in the aperture. To first order, the temporal length of the optical pulse will be a function of the width of the excess minority carrier packet, the width of the aperture, and the drift velocity of the excess minority carriers. In p-type gallium arsenide, geometric scales of 5 μm should make possible pulse widths near 100 ps. Initial experimental results are presented confirming the spatial displacement and the attenuation of the external luminescence intensity as a function of applied bias voltage.