Transverse acoustoelectric voltage measurements of GaAs grown directly on (100) Si substrates

摘要

Transverse acoustoelectric voltage (TAV) measurements have been analyzed as a function of incident photon energy, dc bias voltage, temperature, and surface acoustic wave (SAW) frequency of GaAs layer (∼1.4 mgr;m thick) grown on a vicinal Si(100) substrate by molecular‐beam epitaxy. The TAV technique is used to show that the band gap and impurity level transitions are of slightly lower energies, compared to the bulk GaAs. This might be due to the residual strain changes in the band structure of GaAs grown on Si. It is also noticed that the presence of an interface considerably changes the shape of the experimental TAV versus bias voltage at low temperatures. Drastic variations of TAV as a function of SAW frequency and temperature are also observed. The cause of variations is not yet clear, but possible explanations are discussed.