Three-dimensional transport imaging for the spatially resolved determination of carrier diffusion length in bulk materials.

Rev Sci Instrum

Department of Mathematics, US Military Academy, West Point, New York 10996, USA.

Published: April 2012

A contact-free optical technique is developed to enable a spatially resolved measurement of minority carrier diffusion length and the associated mobility-lifetime (μτ) product in bulk semiconductor materials. A scanning electron microscope is used in combination with an internal optical microscope and imaging charge-coupled device (CCD) to image the bulk luminescence from minority carrier recombination associated with one-dimensional excess carrier generation. Using a Green's function to model steady-state minority carrier diffusion in a three-dimensional half space, non-linear least squares analysis is then applied to extract values of carrier diffusion length and surface recombination velocity. The approach enables measurement of spatial variations in the μτ product with a high degree of spatial resolution.

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http://dx.doi.org/10.1063/1.3698090DOI Listing

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