Theory of Relation Between Hole Concentration and Characteristics of Germanium Point Contacts

material. In the case of metal-point contacts to high-purity M-type germanium, such as is used in transistors and high-back-voltage varistors, it is necessary to consider flow by both electrons and holes. A large part of the current in the direction of easy flow (metal point positive) consists of holes which flow into the >/-type germanium and increase the conductivity of the material in the vicinity of the contact. -' The conductivity is increased not only by the presence of the added holes but also by the additional conduction electrons which flow in to balance the positive space charge of the holes. There is a small concentration of holes normally present in the germanium under equilibrium conditions with no 2 For a discussion of the nature of current flow in semi-conductors see the "Editorial Note" in Bell Sys. Tech. Jour. 28, 335 (1949). J. Bardeen and W. H. Brattain, Bell Sys. Tech. Jour. 28, 239 (1949). W. Shockley, G. L. Pearson and J. R. Haynes, Bell Sys. Tech. Jour. 28, 344 (1949). 469 1 2 s