Lead strontium sulfide and lead calcium sulfide, two new alloy semiconductors

Abstract

The pseudobinary alloy ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{S}$ exists as a single phase at all compositions. With change in composition the optical absorption edge at 300 K changes continuously from 0.4 eV for PbS to 4.6 eV for SrS. For compositions with $x\ensuremath{\le}0.2$, $p$-type and $n$-type thin films have been prepared by doping with Tl or Ag and with Bi, respectively. Similar single-phase behavior and composition dependence of the energy gap are found with ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}\mathrm{S}$.