ELEG 867 - Devices for Light Detection from the Submillimeter to the Ultraviolet – Fall 2009 Homework #8 - due Friday, 30 October 2009, in class 1. Which is better – a p-on-n solar cell, or an n-on-p? Assume that the solar cell has the “classic” structure of a thin emitter grown onto a thicker absorbing base. Answer this question in two parts by discussing two collection processes. (a) First, address the differences in minority carrier diffusion length that would favor the transport of one of the carriers in a thicker layer. (b) Second, discuss the effect of different carrier diffusivity in a region where both electrons and holes are generated. The higher diffusivity carrier moves away more quickly, producing a charge displacement and potential difference. This is called the Dember Effect, and the Dember potential can affect Voc. 2. For the Ge cell in problem 1, estimate the optimum load resistance so that the cell will operate near the maximum power point. Make reasonable estimates using the information provided and
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