Diffused Junction Diodes of PbSe and PbTe

A technique is described for producing diffused p‐n junctions in Pb salt single crystals which utilizes an interdiffusion mechanism to introduce controlled deviations from stoichiometry, excess Pb giving rise to n‐type and excess Se and Te to p‐type and , respectively. An analysis of the p‐n junction depths on the basis of Fick's law of diffusion results in the following effective interdiffusion constants: for producing a p‐layer on n‐type PbSe at 600°C; for an n‐layer on p‐type PbSe at 650°C; for an n‐layer on p‐type at 650 °C. In the first case the diffusion has been studied as a function of time, and the results show that the assumption of Fick's law of diffusion was valid. As expected the interdiffusion constants are two to three orders of magnitude larger than the self‐diffusion constants. Electrical characteristics of the diffused diodes are presented and can be explained as resulting from a combination of diffusion and tunneling current components.