We have investigated the fabrication of the PbS single crystal with well-developed facet under the vapor pressure of sulfur. The relation between the vapor pressure of sulfur p(S) and the growth temperature T-g followed the expression as log(p(S))=38-37410 T-g(-1), when the faceted PbS single crystal was obtained. The conductivity type of the crystals changed from n-type to p-type in the vicinity of 100 Pa for p(S), and the carrier concentration varied from 10(16) to 10(18) cm(-3) at 77 K with respect to p(S). This means that the deviation from stoichiometry in the faceted PbS single crystal can be controlled by p(S). The flat surface thus obtained in the as-grown (10 0) facet allows us to use as a substrate directly for the mid-infrared laser without any mechanical polishing and chemical etching. (C) 2002 Elsevier Science B.V. All rights reserved.