An analysis was made of minority carrier diffusion and collection, in a semiconductor with a surface junction, in the presence of a periodic array of straight dislocations oriented perpendicular to the surface. A dislocation was characterized by its line recombination velocity and was accorded a finite cross-section. An approximate solution was obtained for the three-dimensional charge collection probability in the unit cell of the array. The integral of the collection probability over the unit cell was used to introduce a new definition of effective diffusion length and to derive an analytical expression. It was shown that the relative reduction in diffusion length which was produced by the dislocation array agreed with the fractional decrease in the total number of junction-injected carriers. This established a connection between the efficiency of charge collection and the luminescence of a sample which contained dislocations. The analysis was extended to the case of a thin sample, and was compared with previous treatments of the same problem. The consequences of the theory were illustrated by numerical examples and by its application to published experimental data.

Modeling the Effect of Dislocations on the Minority Carrier Diffusion Length of a Semiconductor. C.Donolato: Journal of Applied Physics, 1998, 84[5], 2656-64