Dependence of photoluminescence spectra of epitaxial Pb1 − xEuxTe (0 ≤ x ≤ 0.1) alloy layers on conditions of growth

The photoluminescence spectra of the Pb1 − x Eu x Te (0 ≤ x ≤ 0.1) alloy are studied at low temperatures. Epitaxial layers were grown by molecular-beam epitaxy at different temperatures. Along with the basic line corresponding to interband radiative recombination, additional emission lines are observed in the low-energy region of the spectra. Some nonuniformities are observed at the sample surface (within an area smaller than 1% of the total surface area). The concentration and size (1–10 μm) of the nonuniformities decrease with increasing temperature of growth. The additional emission lines are attributed to local nonuniformities in the layer. The dependence of the band gap of the Pb1−x Eu x Te (0 ≤ x ≤ 0.1) alloy on the composition parameter x is determined at 77.4 K. The dependence is nonlinear and adequately described by the relation E g [eV] = 0.213 + 4.8x − 18.4x 2.