It is shown that the current collected by a p-n junction in presence of a unit point generation of carriers at a point P is the same (apart from the dimensions) as the excess minority-carrier density at P due to a unit density of carriers at the junction edge. Use of this reciprocity relation may simplify the calculation of beam induced currents in semiconductor devices. The practical meaning of this property is illustrated in the case of a light-emitting diode containing defects.

An analysis is given of the minority carrier diffusion and collection in a semiconductor with a surface junction, in the presence of a periodic array of straight dislocations perpendicular to the surface. A dislocation is characterized by its line recombination velocity and is attributed a finite cross section. An approximate solution is obtained for the three-dimensional charge collection probability φ(r) in the unit cell of the array. The integral of φ over the unit cell is used to introduce a new definition of effective diffusion length and to give its analytical expression. It is shown that the relative reduction of diffusion length produced by the dislocation array coincides with the fractional decrease of the total number of junction-injected carriers. This result establishes a connection between the efficiency of charge collection and luminescence of a sample containing dislocations. The analysis is extended to the case of a thin sample, and is compared to previous discussions of the same problem. The consequences of the theory are illustrated by numerical examples and applications to published experimental data.

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A three-dimensional analysis is given of the generation, diffusion, and collection of minority carriers injected b y an electron beam in a semiconductor containing a p-n junction parallel to the surface. Using a modified Gaussian approximation to the three-dimensional electron beam dissipation function, analytical expressions are derived for the distribution of beam-generated minority carriers in the top layer of the junction and for the collected current. These expressions are used in Part I1 for describing the formation of the contrast in charge-collection images of dislocations, as obtained in scanning electron microscopes.Es wird eine dreidimensionale Behandlung der Erzeugung, der Diffusion und der Sammlung der durch einen Elektronenstrahl erzeugten MinoritStsladungstriiger in einem Halbleiter mit einem zur Oberflache parallelen Ubergang gegeben. Unter Verwendung einer modifizierten GauDschen Naherung zur dreidimensionalen Verteilung der durch den Elektronenstrahl erzeugten Ionisierungsdichte, werden analytische Ausdriicke fur die Verteilung der strahlerzeugten MinoritLtsladungstrager in der oberen Schicht des Ubergangs und fur den gesammelten Strom abgeleitet. Diese Ausdriicke werden im 11. Teil zur Beschreibung der Kontrastentstehung bei der-Abbildung von Versetzungen mittels Ladungssammlung in Rasterelektronenmikroskopen verwendet.

A theoretical analysis is given of the induced current profiles at grain boundaries in polycrystalline solar cells, as obtained by light or electron beam excitation. The area A and the variance σ2 of the contrast profile of a grain boundary are calculated for realistic generations as functions of the interface recombination velocity vs and the minority carrier diffusion length L. A graphical new procedure is proposed which allows the simultaneous determination of vs and L from the measured values of A and σ. The evaluation of an experimental electron beam induced current profile illustrates the applicability of the theory.