Volume 83, Issue 2, 15 January 1998
Index of content:
83(1998); http://dx.doi.org/10.1063/1.366808View Description Hide Description
We present a procedure that locally determines the composition (from a given set of available materials) of a segmented or graded thermoelectric generator leg in order to maximize its output power to a matched load. The method is based on a new interpretation of the electrical output relation, which is organized to resemble a differential output power along the device coordinate. The procedure is applied to calculate the segment length and output power of a segmented bismuth-telluride/iron-disilicide based thermoelectric generator leg.
Scanning cathodoluminescence as a probe of surface recombination in phosphors excited at low electron energies83(1998); http://dx.doi.org/10.1063/1.366809View Description Hide Description
Scanning cathodoluminescence (SCL) is a technique that has been widely used to categorize local minority carrier lifetime nonuniformities in bulk and thin filmsemiconductors. In the case of phosphorpowders it has been less popular, partly because the collection and scattering of light generated in an array of particles complicates the extraction of quantitative information about light generation efficiency. Here we demonstrate that by coupling SCL with modern digital imaging manipulation techniques, we can extract quantitative information about the beam energy dependence of phosphorcathodoluminescence with high spatial resolution. A number of common phosphors are examined and a wide range of behavior is observed. We find that materials like ZnS:Ag and display uniformly high nonradiative surface energy losses, while other materials like ZnO:Zn have surface losses which are spatially very nonuniform.