Oscillatory Magneto-Absorption of the Direct Transition in Germanium

Infrared transmission of intrinsic germanium was examined at wavelengths from 1.4μ to 1.6μ in constant magnetic fields up to 36 000 gauss. The magneto-absorption showed oscillatory behavior at photon energies greater than that of the direct transition. The energy gap of the direct transition was determined experimentally to be 0.803±0.001 ev at room temperature. The effective mass of the electron in the ${\Gamma }_{2^{-}}$ conduction band was found to be $\approx 0.042m_0$. Anisotropy of the oscillations was observed as a function of the orientation of the sample in the magnetic field.