The determination of transport parameters of minority carriers in n– p junctions by means of an electron microscope. Critique of recent developments

Abstract

It has recently been shown that amplitude modulated electron beams provide a novel means for the determination of minority carrier lifetimes, diffusion lengths, etc. in n– p junctions. In this paper we show that (a) a recently published analysis based on a cylindrically symmetric configuration is incorrect, (b) the correct approach leads to a system of dual integral equations for which the formal solution is given, (c) in general, the short circuit current can only be determined by means of extensive computer calculations except in the case of large front surface recombination velocities, (d) the difficulties encountered with cylindrically symmetric configurations (circular ohmic contacts and the like) are completely avoided with a choice of a planar geometry since simple closed form expressions for the short circuit current are readily available in this case.