  Electron irradiation is investigated as a way to dope the topological
insulator Bi2Te3. For this, p-type Bi2Te3 single crystals have been irradiated
with 2.5 MeV electrons at room temperature and electrical measurements have
been performed in-situ as well as ex-situ in magnetic fields up to 14 T. The
defects created by irradiation act as electron donors allowing the compensation
of the initial hole-type conductivity of the material as well as the conversion
of the conductivity from p- to n-type. The changes in carrier concentration are
investigated using Hall effect and Shubnikov-de Haas (SdH) oscillations,
clearly observable in the p-type samples before irradiation, but also after the
irradiation-induced conversion of the conductivity to n-type. The SdH patterns
observed for the magnetic field along the trigonal axis can be entirely
explained assuming the contribution of only one valence and conduction band,
respectively, and Zeeman-splitting of the orbital levels.
