Natural PbS crystals were exposed to various pressures of sulfur-vapor near 500°C and then quenched. Calculations based on the penetration of $p-n$ junctions gave an interdiffusion constant of 2×${10}^{-6\mathrm{}}$ ${\mathrm{cm}}^2$/sec at 550°C. The temperature dependence of the Hall coefficient and resistivity for several treated crystals was determined. A forbidden energy gap of 0.37±0.01 ev and an electron to hole mobility ratio of 1.4 was obtained.

• Received 21 June 1954

DOI:https://doi.org/10.1103/PhysRev.96.598