Saturation of red Zn-O electroluminescence in gallium phosphide diodes

Liquid-phase epitaxial n-type layers, grown on pieces from the same p-type solution-grown substrate (0.07m%Zn, 0.02m%Ga2O3in melt), with a variable tellurium concentration in the tipping charge, have been investigated. Two groups of mesa diodes were fabricated (junction-area is 7.3 × 10^-4cm^-2): (1) from as-grown p-n layers and (2) from layers annealed in forming-gas (600°C, 6 hr). Electrical and optical measurements have been made on these diodes to learn about the physical processes limiting diode efficiencies.