Determination of the Donor–Acceptor Pair Separation in GaP Semiconductor Doped with Sulfur and Zinc Using its Photoluminescence Spectrum

Abstract

Considering the gallium phosphide (GaP) semiconductors doped with sulfur (S) and zinc (Zn) acceptors, we have studied the behavior of Huang-Rhys factor S theor as a function of the donor–acceptor (D–A) pair separation R. It turned out that the form of the bands — broad or narrow — that are attributed to (D–A) recombination, depends on the values of the pair separation — large or small, respectively. More specifically for R=0.5 nm we obtain S theor =0.117 and for R=3.5 nm, S theor =3.616. The above values of the factor S impose sub-Poissonian (with ℏω=49.97 meV) and super-Poissonian (with ℏω=78 meV) distribution shapes on the bands.