A deep center associated with the presence of nitrogen in GaP

Abstract

The deep−level thermal activation energy spectrum of N−doped liquid−phase−epitaxial (LPE) and liquid−encapsulated−Czochralski (LEC) −grown GaP has been investigated using Schottky barrier thermally stimulated−current (TSC) measurements. We detect a center at E_c−E_t=0.42 eV whose presence in the lattice depends on the deliberate addition of N to the material. The concentration of this center varies approximately as (N_d−N_a)² in n−type material, and the value of electron capture cross section for the center (S_t≈7×10⁻¹⁵ cm²) indicates that it could be a strong recombination center in N−doped p−type GaP. Separate experiments suggest that this center is strongly localized, and that it is not a simple complex involving shallow donors and native defects.