A study of lifetime in germanium containing nickel impurities has shown that the recombination process must be interpreted in terms of a multilevel model, with three charge states assigned to nickel. At room temperature the electron-capture cross section of neutral nickel is 0.96×${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$, and that of singly negative nickel is 5.9×${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$; the capture constants in both cases are independent of temperature. The cross section of doubly negative nickel for holes is approximately 1×${10}^{-14\mathrm{}}$ ${\mathrm{cm}}^2$; no information on the temperature dependence of this cross section has been obtained. Lifetime data are in good agreement with the known energy levels and solid solubility. The results are compared with those in the literature.

• Received 6 February 1959

DOI:https://doi.org/10.1103/PhysRev.115.37