Epitaxial wide band gap Pb1-xSrxSe (x > 0.9) layers have been successfully grown by molecular beam epitaxy on Si(1 1 1) and BaF2(1 1 1) substrates. Reflection high-energy electron diffraction (RHEED) showed that layers on both substrates were single crystal and oriented to the substrate. X-ray diffraction showed that layers on Si(1 1 1) were high quality as indicated by full-width at half-maximum (FWHM) values of less than 300 arcsec. These results provide a foundation for the eventual fabrications of ultraviolet detector arrays and high power-integrated circuits on silicon substrates.