ELECTRICAL PROPERTIES OF ELECTRON IRRADIATED GERMANIUM

Measurements of the electrical properties of arsenic -doped germanium irradiated at 300K with electrons and annealed at high temperatures are reported. Bombardments with 1.5 Mev electrons on 1.2 ohm-cm n-type material caused the conductivity to decrease initially to a minimum value after being irradiated with 7 x 10 to the 15th power electrons/sq cm, and then to increase slowly with additional radiation. The negative Hall coefficient increased at first, and then exhibited a reduction when the fluence increased beyond 7 x 10 to the 15th power electrons/sq cm. Hall effect measurements indicated that the material converted to p-type following a fluence of 1.1 x 10 to the 16th power electrons/sq cm. Conversion was observed after the conductivity passed the minimum value. A small decrease of two per cent in the Hall mobility following a fluence of 7 x 10 to the 14th power electrons/sq cm was produced. The data indicated that the carrier removal rate was .6 carriers/electron cm. In irradiated 16 ohm-cm n-type material which had been converted to p-type, reversion occurred rather quickly at an annealing temperature of 312K. The annealing rate was slower following the maximum resistivity and negative Hall coefficient values. The sample was not restored to its pre-irradiated condition following the highest annealing temperature conducted. (Author)