Light Emission from Reverse Biased GaAs and InP p-n Junctions

Abstract

The light emission from reverse‐biased diffused p‐n junctions made in the direct band gap semiconductors GaAs and InP has been measured. In addition to the broad emission spectrum observed from junctions in other materials which have indirect band gaps, a sharp line (Δλ≅150 Å) is observed at photon energies slightly less than the energy gap. In most diodes this line dominates the spectrum. It is almost identical in shape to the line observed at this photon energy when the junction is forward biased. The measured external quantum efficiency of the reverse biased light is higher (∼10⁻⁵ to 10⁻⁴) than has been reported for most other materials. The spatial distribution of the light emission and the current‐voltage characteristics have also been found to be similar to those of other materials.