Hall Effect and resistivity measurements on semiconductors − implanted with radioactive ions − are able to reveal additional aspects of the material. Properties like resistivity and carrier concentration, which are measured by the corresponding non-nuclear method, are influenced by the time dependence of the nuclear decay. Implanted radioactive ions decay exponentially and may change their electrical behaviour in the semiconductor if the doping characteristics of the new atoms are different. Thereby: the macroscopic quantities resistivity and carrier concentration change.
The conclusions that these measurements provide are often useful to gather information complementary to techniques like Perturbed Angular Correlation (PAC) for the investigation of defects in semiconductors. Nevertheless, the results of such Radio-Hall Effect measurements are interesting in their own right.
Hall effect and resistivity measurements were performed on semi-insulating InP implanted with 111In → 2.8d → 111Cd) in order to study the p-type doping of Cd in InP. The activation of acceptors in InP is harder to achieve than the activation of donors and the results are always inferior. To avoid this problems, we implanted 111In which during the annealing procedure is incorporated on the In sub-lattice and there decays to Cd.
The samples (s.i. InP) were implanted with 111In at a total dose of about 1·1012 cm-2. The 111In-implantation have been performed at 80 keV. The hall- and resistivity measurements on these slightly doped samples, only a few percent of the dose have been In, were partly successful. Because of the high resistivity of the samples, we weren't able to do the hall-measurements. The time-dependence of the specific resistivity, however, showed the activation of the Cd. Further investigations, on p-type InP too, will show more details.