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

Heavily doped and fully compensated Ge single-crystalline thin (∼0.1μm) films were epitaxially grown in vacuum on semi-insulating GaAs substrates. Such films have high resistivity (up to 140Ω∕cm), conductance activation energy as high as half the band gap of Ge, low free charge carrier mobility (∼50cm2∕V⋅s) and concentration (∼1014cm−3). The transport properties of the films were studied and explained involving the theory of two-dimensional potential fluctuations and percolation.