Determination of the Conduction Band Effective Masses of the Germanium—Silicon Alloy by Infrared Cyclotron Resonance

Cyclotron resonance measurements have been performed on the conduction bands of germanium‐silicon alloys at 891 GHz (337 pm) using an infrared laser. This has enabled measurement of the longitudinal and transverse effective masses to within 4 at% of each side of the alloy composition at which the conduction band edge switches from the [111] to the [100] direction (15 at% Si in Ge). The masses do not appear to change from their values in the pure constituents, although only the transverse mass of the [111], Ge‐like, minimum was measured with good accuracy. Within 3 at% of the switch‐over concentration, intervalley scattering becomes predominant; throughout the rest of the alloy system, disorder scattering predominates and the scattering frequency obeys an x(1 − x) law.