Hall effects and noise measurements in epitaxial, polycrystalline, and amorphous Ge

Data are given of the hall mobility, carrier concentration and conductivity for epitaxial, polycrystalline, and amorphous Ge films over a temperature range 100 to 400 K; all specimens are found to be p-type. The room temperature noise spectra for these films are also given. It is found that amorphous films can be characterised by the presence of generation–recombination noise with time constants of 4.5 × 10−3 and 2 × 10−5 s wheras in crystalline films only 1/f noise is present. An activated mobility was found for unannealed amorphous films and the data agrees with present theories remarkably well except that the apparent hole concentration falls with a rise in temperature.