Luminescence quenching and the formation of the GaP1−<i>x</i>N<i>x</i> alloy in GaP with increasing nitrogen content

Abstract

A study of the luminescence properties of epitaxial GaP containing atomic N grown by molecular beam epitaxy using NH3 and PH3 as the column V sources was conducted. The 77 K photoluminescence spectra of the N-doped epitaxial GaP showed a continuous redshift, from 5691 Å (2.18 eV) to 6600 Å (1.88 eV), resulted when the N concentration exceeded ∼5–7×1019 cm−3. This energy shift was found to be consistent with energy gap predictions using the dielectric theory of electronegativity for the GaP1−xNx system. The data also indicate that the emission intensity was maximum for N∼1×1020 cm−3, and then monotonically decreases with increasing N content. This is consistent with the formation of an indirect band-gap semiconductor.