Determination of the Active Region in Light-Emitting GaAs Diodes [Letter to the Editor]

Stimulated emission has been observed recently in GaAs diodes.
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A question of particular interest is the spatial origin of the light. In this Letter it is shown that in high-efficiency units the light clearly comes from the p-region. This is in agreement with the conclusion from fluorescence measurements on homogeneously doped samples of GaAs that an acceptor center is involved in the radiative recombination in p-n junctions.
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Furthermore in a rectangular parallelepiped laser
^3,4
it is found that the appearance of the emitting region does not change as the current is increased above the threshold for stimulated emission.