Deposition and characterization of thin films of germanium

The electrical conductivity, Hall mobility and the Hall coefficient of crystalline germanium films, vacuum-deposited on to heated glass microscope slides, were measured at temperatures varying between 77 K and 400 K using the Van der Pauw technique. Factors responsible for the growth of thin films and their characterization are discussed. The films were found to be p-type, having negative temperature coefficient of resistance, although the starting material was high-purity germanium. On the basis of experimentation, it is shown that the Hall mobility, the Hall coefficient and the electrical conductivity increase with an increase in the thickness of the film and also with an increase in the measurement temperature.