Free‐exciton radiation from p‐i‐n diodes of GaP doped with indium and oxygen

GaP diodes containing indium and oxygen emitted intense green light (2.23 eV) with weak red light (1.77 eV) at room temperature. The green light emission was enhanced by In and the spectral measurements revealed the green light to be due to the simultaneous annihilation of a free exciton and a LA phonon. The diode had a p‐i‐n structure, and the green light was emitted from the intrinsic region which was formed by oxygen deep donors. At appropriate oxygen concentrations, diodes which emit only green light were fabricated successfully.