Effects of uniaxial stress on GaAsP red-light-emitting diodes

Abstract

GaAsP red-light-emitting diodes containing 40% phosphorus were stressed uniaxially in the [100] direction at 77 K. The spectral emission peak was observed to shift to higher energies at the rate of 2.1 ± 0.2 meV/kbar. From the stress dependence of the recombination current, the band-gap stress coefficient is 3.6 ± 0.3 meV/kbar. By using the fact that radiative recombination takes place via a band-acceptor (Zn) process, it is concluded that the acceptor level moves away from the valence band at the rate of 1.5 ± 0.4 meV/kbar. The intensity-voltage characteristic is consistent with the interpretation that the effect of the uniaxial stress is to deionize the acceptor level, which causes a smaller decrease of intensity with stress than would be expected from band-gap deformation alone. The effect of uniaxial stress on the indirect-direct conduction-band transition is discussed.