Transverse Noise of Hot Electrons in n-Type Germanium

Abstract

This work is an extension of previous analysis of high-field, hot-electron noise in n-type germanium. The previous analysis, developed to explain the author's observations of field-direction (longitudinal) noise, is extended here in an attempt to explain the hot-electron, transverse noise observations of Erlbach and Gunn.In the model adopted, the transverse current fluctuations, resulting from intravalley and intervalley scattering, within the interelectrode volume (electrode area × separation), yield both thermal and intervalley contributions to the noise temperature. For two of the three crystal orientations considered, the intervalley noise is negligible, but in the third case, the two contributions are of the same order.Individual valley currents, populations, and relative intervalley transition rates are calculated from Nathan's analysis, and the Barrie–Burgess theory of high-field transport provides the valley electron temperatures. The intervalley scattering data of Weinreich, Sanders, and White yield absolute values of the intervalley scattering probabilities.Poor agreement is found with the Erlbach–Gunn observations of transverse noise temperature, which may be due to the shunting effect of the portion of the sample exterior to the interelectrode volume.