Session CB: Materials I
10:45 AM–12:33 PM, Thursday, November 9, 2006
Williamsburg Hospitality House Room: Jamestown
Chair: Mary Ellen Zvanut, University of Alabama at Birmingham
Abstract ID: BAPS.2006.SES.CB.8
Abstract: CB.00008 : Modeling defect level occupation for recombination statistics
12:09 PM–12:21 PM
Authors:
Adam Topaz
Tim Gfroerer
(Davidson College)
Mark Wanlass
(NREL)
Measurements of luminescence intensity as a function of temperature and laser illumination can provide considerable insight into the energy level distribution and recombination statistics of a semiconductor. Since the radiative recombination rate is proportional to the product of carrier densities in the valence and conduction bands, measurements of radiative efficiency vs. photoexcitation reveal how non-radiative, defect-related recombination mechanisms vary with band occupation. In this context, recent experimental results for a high-quality GaAs/GaInP double heterostructure contain two informative features. First, the radiative efficiency increases with temperature, indicating that shallow nonradiative recombination centers are being thermally depleted. Second, the defect-related recombination rate increases unusually slowly against the band carrier density product. Using a sophisticated model for non-equilibrium band and defect level occupation, we show that this latter result requires an asymmetric distribution of defect levels within the gap. Trap filling produces a rapid increase in that carrier’s band occupation, while the density of carriers in the band responsible for defect-related recombination remains nearly constant, such that the product increases without augmenting the recombination rate appreciably.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2006.SES.CB.8