Electroluminescence in GaAsxP1−x, InxGa1−xP, and AlxGa1−xP Junctions with x≲0.01

Abstract

The addition of low concentrations (≲1%) of As, In, or Al to the p side of GaP junctions, where exciton recombination at N or Zn, O centers generates green and red electroluminescence (EL), respectively, drastically decreases the quantum efficiency η of the junctions. The decrease in η is due to increased nonradiative recombination at deep centers in the junction space charge, while recombination outside the space charge is unchanged according to measurements of the EL decay time. Low‐temperature photoluminescence efficiency measurements confirm that recombination in the bulk semiconductor is unaffected by the presence of these low concentrations of As, In, and Al. The junctions were formed using liquid epitaxial techniques. Using In_xGa_1−xP layers, where the alloy composition was accurately determined using radioactive tracer techniques, the composition dependence of the transition energies of the N and S bound excitons was measured by low‐temperature absorption and luminescence studies.