Fluctuations in Luminescent Junctions

Optical‐emission fluctuations from three types of GaAs and Ga(AsP) p‐n junction luminescent diodes have been examined. Characteristic time constants of 12×10−3 and 0.45×10−3 sec are observed in both the optical noise spectra and forward‐current noise spectra of a GaAs diode in which carrier recombinations occur in the junction space‐charge region. More heavily doped junctions (∼1019 cm−3), in which tunnel currents predominate, exhibit 1/f noise. In either case, correlation exists between optical‐emission noise and forward‐current noise, suggesting that carrier transitions responsible for both effects are the same. Only simple photon noise is observed from a Ga(AsP) diode in which junction diffusion currents are significant, although the forward noise spectrum is also 1/f noise.