Liquid Phase Epitaxy of Thin Isoperiodic Heterostructures of Pb1 – xSnxTe1 – ySey Solid Solutions

Results of the study of the initial stages of growth by the liquid phase epitaxy (LPE) method of isoperiodic structurally advanced heterostructures (HSs) based on solid solutions of the Pb-Sn-Te-Se system are presented in the paper. Theoretical analysis has shown that three principally different cases can be distinguished for the growth of Pb1 – xSnxTe1 – ySey multicomponent solid solutions (MSS) on PbTe0.88Se0.12 and Pb0.70Sn0.30Te substrates. It is shown that for Pb0.70Sn0.30Te substrates in the case where the substrate and the epitaxial layer (EL) are isoperiodic at some average temperature between the growth temperature and the operating temperature of the device, it is possible to obtain ELs with the red photoelectric limit of 16-24 μm at operating temperatures, for which critical thicknesses ≥ 4 μm, by the LPE method. The peculiarities of the LPE technology of quasi-isoperiodic HS obtaining, used in the work, equipment and methods of research are described. For example, at low cooling rates (0.1 < v < 0.3 K∕min), regardless of the temperature reduction range, which varied within 1.0 < ∆T < 5.0 K, mirror-smooth ELs with a thickness of 1-3 μm and the surface dislocation density of less than 2·105 cm – 2 were obtained. However, the study of the substrate/layer interface showed the formation, although thin ∼ 0.2-0.4 μm, of transition layers. Further experimental studies have shown that a more promising LPE technology in this case is the method of pre-cooling of the solution-melt. At programmatic lowering of the temperature with velocity v < 0.3 K∕min and initial cooling of 1-3 K, ELs were either mirror-smooth or had a light terraced structure, which may be due to the slight misorientation of the substrates relative to the growth plane.