PbSe Composition Stability Limits

Abstract

Pb‐saturated and Se‐saturated PbSe have been prepared by equilibrating small single crystals with two‐phase ingots rich in either Pb or Se and quenching to room temperature. The Hall constant and conductivity were then measured. Pb‐saturated PbSe is n‐type with a room‐temperature electron concentration that increases with increasing equilibration temperature from about 1.7×10¹⁸ cm^—3 at 500°C to 1.4×10¹⁹ cm^—3 at 800°C. The carrier concentrations are independent of quench rate in the range used and are proportional to exp (— E/kT) with E=0.49 ev. Se‐saturated PbSe is p‐type, the room temperature hole concentration definitely depending on the quench rates used at 600°C and above. The hole concentrations are between 3 and 6.5×10¹⁸ cm^—3. Near 600°C, PbSe exists as a stable phase over a composition range whose limits are roughly symmetric about the stoichiometric composition and which is at least 0.012 atomic percent wide.