Evaluation of diffusion length and surface‐recombination velocity from a planar‐collector‐geometry electron‐beam‐induced current scan

For performing electron‐beam‐induced current (EBIC) measurements on sufficiently large samples, the use of a ‘‘planar‐collector geometry’’ (i.e., with the collector covering part of the irradiated surface itself) is very attractive. However, the pertinent theoretical EBIC curves for finite surface‐recombination velocities s have so far been lacking. This paper presents the complete theoretical expressions for arbitrary values of s and diffusion length L. Simple asymptotic solutions are given for point‐ and finite‐size generation sources. Easy methods are developed to facilitate the application of these solutions in the practical evaluation of L and s from experimental EBIC curves. These methods are applied to experimental data available through the literature.