INFLUENCE OF IRRADIATION WITH 60Co gamma RAYS ON THE STATE OF Ni AND Ag IMPURITIES IN GERMANIUM.

A study was made of the electrical properties of p-type Ge:Ni:Sb and Ge:Ag:Ga crystals irradiated at T less than equivalent to 330 degree K with **6**0Co gamma rays. Irradiation reduced the concentration N//s of the Ni and Ag impurities in the electrically active state and generated radiation acceptors with levels below E//v plus 0. 06 eV in concentration comparable with DELTA N//s equals N//s(init)-N//s(irr). Isochronous annealing of the irradiated samples revealed a negative stage in the temperature range 470-590 degree K, where the value of N//s decreased and shallow-level acceptors were generated; these acceptors disappeared at T greater than 770 degree K without recovery of the electrical activity of the silver and nickel atoms at the lattice sites. The deactivation of the Ni//s** minus and Ag//s** minus impurities and introduction of shallow-level acceptors by irradiation and subsequent annealing were attributed to the formation of Ni//sGe//i and Ag//sGe//i complexes.