Minority-carrier lifetimes and luminescence efficiencies in nitrogen-doped GaP

Abstract

Photoluminescence and scanning‐electron‐microscope measurements of minority‐carrier lifetime and luminescence efficiency have been made on Zn, N‐doped and Te, N‐doped GaP liquid‐phase‐epitaxy layers. Nitrogen concentrations are held constant at 1 × 10¹⁹ cm⁻³, while the majority‐carrier concentrations were varied between 5 × 10¹⁶ and 5 × 10¹⁸ cm⁻³. It is shown that, for excitation levels equivalent to 10 A/cm² diode diffusion current density, a maximum external luminescence efficiency (in air) of 0.3% is measured for ∼10¹⁸‐cm⁻³ Zn, N‐doped GaP, in contrast to a maximum efficiency of 0.06% for ∼10¹⁷‐cm⁻³ Te, N‐doped GaP. These results suggest that significantly higher electroluminescent efficiencies approaching 0.3% are available for diodes at 10 A/cm², by increasing injection into ∼10¹⁸‐cm⁻³ Zn, N‐doped GaP.