Heavily doped and fully compensated Ge single-crystalline films on GaAs

Heavily doped and fully compensated Ge single-crystalline thin (similar to 0.1 mu m) films were epitaxially grown in vacuum on semi-insulating GaAs substrates. Such films have high resistivity (up to 140 Omega/cm), conductance activation energy as high as half the band gap of Ge, low free charge carrier mobility (similar to 50 cm(2)/V(.)s) and concentration (similar to 10(14) cm(-3)). The transport properties of the films were studied and explained involving the theory of two-dimensional potential fluctuations and percolation. (C) 2008 American Institute of Physics.