Influence of Different Solvents on the Quality of Epitaxial Layers in Pb-Sn-Te-Se Systems

Abstract

(en) The article is devoted to the study of various solvents influence on the quality of epitaxial layers A4B6 type semiconductor compounds growing during liquid-phase epitaxy. The choice of such compounds was primarily due to the instrumental characteristics of the obtained structures based on lead-tin chalcogenides, which are competitive in comparison with A2B6, among which there are significant sensitivity, response speed, thermal and radiation resistance, spectral homogeneity, and low noise level. The use of multicomponent heterolayers of the Pb1 – xSnxTe1 – ySey type makes it possible, by changing the composition, to control the band gap and, within certain limits, to match the parameters of the substrate and the epitaxial layer crystal lattices. In addition, such advantages of liquid-phase epitaxy as low growth temperatures, relatively simple equipment, short duration and cost of the processes, make it possible to continue research in the above direction. The analysis of the possibility of using In, Ga, Cd, Te, Bi and other solvent metals as alternatives to lead for growing by liquid epitaxy of solid solutions in the Pb-Sn-Te-Se system has been carried out. The use of only solvents based on Te, Tl, Bi in experimental studies is substantiated. In particular, the epitaxial growing with a tellurium solvent demonstrated that use of Bi (for concentrations of 50 atomic %) significantly affected not only the removal of the growth melt, but also the morphology of the grown layers: the surface was free from the wavy relief inherent in epitaxial layers grown from pure tellurium solutionsmelts. The results show the promise of Bi-Te melt solutions using, which make it possible to obtain structurally perfect epitaxial layers of n-type conductivity with a dislocation density of ~10 5cm – 2, a carrier concentration of ~10 18 cm – 3 and a mobility of (103 -104) cm2/Vs at 77 K.