The Microwave Harmonic Generation in Semiconductors at Low Temperatures. I. Germanium

Abstract

The microwave harmonic generation in n-type germanium is observed at liquid helium temperatures and it is found that the third harmonic generation (THG) shows the resonance behavior when the magnetic field is changed. The experimental results on the conversion efficiency, anisotropic behavior of the peaks, donor concentration dependence and the input power dependence of the THG are described. It is shown from these characteristics that the resonance type THG arises from the multi-photon resonance of electrons trapped in very shallow impurity states. A model is proposed that such impurity states are the states associated with the donor negative ion (D⁻), and the anisotropic behavior of the resonance field is reasonably interpreted in terms of the orbital Zeemann effect of the D⁻ states.