Growth and characterization of thallium- and gold-doped PbSe0.78Te0.22 layers lattice matched with BaF2 substrates

We report on liquid phase epitaxial growth and Hall effect characterization of thallium- and gold-doped PbSe0.78Te0.22 layers lattice matched with BaF2 substrates. Thallium behaved as an acceptor allowing growth of compensated p-type PbSe0.78Te0.22 layers with hole concentrations as high as 2.2×1018 cm−3. (Undoped PbSe0.78Te0.22 epitaxial layers were n-type with electron concentrations of 4.3×1018 cm−3.) The transition from n-type to p-type occurs at approximately 1.2 at. % thallium in the growth solution. Gold also exhibited acceptor behavior for low doping concentrations but behaved as a donor for doping concentrations greater than 1 at. % such that p-type layers could not be obtained. Electron mobilities as high as 7846 cm2/V s at 77 K were measured in this ternary alloy.