Theory of Transient Phenomena in the Transport of Holes in an Excess Semiconductor

A variety of experiments have been performed, and others are planned, which involve measurement of transient or steady-state phenomena due to the drift of positive holes along a specimen of w-type semiconductor after they have been introduced at an injection electrode or emitter.1 These phenomena are presumably a result of the interplay of drift, space-charge, recombination, and diffusion effects. This paper seeks to relate these effects to the phenomena, and its principal contribution is an explicit calculation of the transient phenomena outside the range of small-signal theory, for cases where the geometry is one-dimensional and where certain simplifying assumptions, notably the neglect of diffusion, are justified. Removal of some of these simplifying assumptions and a more careful development of the theory will be necessary in certain applications. Section 1 discusses the physical assumptions and boundary conditions involved in setting the problem up. Section 2 contains calculations of the distribution of holes along the length of the semiconductor at various times, for the mathematically simplest case where recombination and diffusion are ignored and all currents are held constant after the start of the injection. This simple case illustrates the method of attack, to be used in the more general calculations of Section 4, and it is hoped that this sketching of basic ideas will enable the hasty reader to pass on to Section 6 without going 1 Kxperiments of this sort have been undertaken with the objective of testing and extending the theoretical interpretation of transistor action proposed by J.