Growth and electrical properties of epitaxial PbSexTe1minus;xlayers

摘要

Epitaxial layers of PbSexTe1minus;x(0les;xles;1) have been grown on the (111) faces of cleaved BaF2and SrF2single crystals by vacuum deposition of the evaporated binary compounds. Structural studies indicate that the layers are single crystals with widely spaced lowhyphen;angle grain broundaries that propagate from the substrates. Due to the smaller thermal expansion of the substrate the layers are strained, except atx=0 andx=1. The functional dependence of the elastic strain on layer composition, egr;prop;x(1minus;x), and its magnitude suggest that the thermal expansion and/or elastic constants of PbSexTe1minus;xare nonlinear functions ofx. The Hall mobilities decrease from about 1times;103cm2/Vthinsp;s (300 K) and 3times;104cm2/Vthinsp;s (77 K) atx(1minus;x) =0 to about 3times;102cm2/Vthinsp;s (300 K) and 5times;103cm2/Vthinsp;s (77 K) atx=0.5, apparently as a result of alloy scattering.