title: Three-dimensional transport imaging for the spatially resolved determination of carrier diffusion length in bulk materials.
abstract: 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.
authors.affiliation: Department of Mathematics, US Military Academy, West Point, New York 10996, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Blaine
authors.forename: D J
authors.initials: DJ
authors.lastname: Phillips
authors.forename: C L
authors.initials: CL
authors.lastname: Frenzen
authors.forename: C
authors.initials: C
authors.lastname: Scandrett
authors.forename: N M
authors.initials: NM
authors.lastname: Haegel