Physical properties and efficiency of GaNP light emitting diodes

GaNP /GaP is promising for yellow-amber-red light emitting diodes LEDs . In this study, pressure and temperature dependent electroluminescence and photocurrent measurements on bulk GaP /GaN0.006P0.994 /GaP LED structures are presented. Below 110 K, emission is observed from several localized nitrogen states. At room temperature, the band-edge energy increases weakly with pressure at a rate of +1.6 meV /kbar, substantially lower than the band gap of GaP +9.5 meV /kbar . Thus, despite the multiplicity of nitrogen levels, the band anticrossing model reasonably describes this system based on an average of the nitrogen states. Furthermore, carrier leakage into the X minima of GaP reduces the efficiency in GaNP-LEDs with increasing pressure. © 2008 American Institute of Physics. DOI: 10.1063/1.2830696