Electrical Transport in nGe-pGaAs Heterojunctions†

Abstract

A multi-step recombination-tunnelling model, similar to that used to describe the excess current in tunnel diodes, is developed to explain the observed electrical characteristics of nGe-pGaAs heterodiodes. Two different, but quite similar models are used to qualitatively describe the observed forward and reverse characteristics. Quantitative agreement with the experimental characteristics of the many devices presented is obtained by an empirical modification of the resulting equations. The lack of minority carrier injection in these devices is in agreement with the proposed model.