@article{brinkley_powell_aspnes_2006, title={Systematic approach for analyzing reflectance-difference spectra: Application to silicon-dielectric interfaces}, volume={88}, ISSN={["1077-3118"]}, DOI={10.1063/1.2204844}, abstractNote={We describe a combinatorial approach for analyzing reflectance-difference/reflectance-anisotropy (RD/RA) spectra that avoids the need to establish null orientations experimentally, suppresses experimental artifacts, signal averages, and allows RD/RA spectra to be assessed systematically for secondary contributions at principal angles different from that of the dominant contribution. Application to rapid-thermal-annealed oxidized and nitrided vicinal (111) Si-dielectric interfaces demonstrates the effectiveness of the procedure.}, number={20}, journal={APPLIED PHYSICS LETTERS}, author={Brinkley, M. K. and Powell, G. D. and Aspnes, D. E.}, year={2006}, month={May} }
 @article{powell_wang_aspnes_2002, title={Simplified bond-hyperpolarizability model of second harmonic generation}, volume={65}, ISSN={["2469-9969"]}, DOI={10.1103/physrevb.65.205320}, abstractNote={We show that the anisotropies of second-harmonic-generation (SHG) intensities of vicinal (111) and (001)Si-SiO 2 interfaces can he described accurately as dipole radiation originating from the anharmonic motion of band charges strictly along bond directions. This simplified bond-hyperpolarizability model not only substantially simplifies the description of SHG, but also provides a microscopically physical and mathematically more efficient picture of the process than those found in standard phenomenological treatments employing tensor or Fourier coefficients. Using this approach we obtain an analytic solution for the expected response of (111) terraces, and by comparing to data show that the effective angles of incidence and observation for the (111)Si-SiO 2 interface are not those measured in the laboratory hut correspond to those refracted at the air-SiO 2 interface. For (111) vicinal interfaces at 765 nm SHG absorption is found to occur mainly for the step bond. The success of this formulation indicates that in many, if not most, cases the description of SHG may be simpler than that of the linear-optical response.}, number={20}, journal={PHYSICAL REVIEW B}, author={Powell, GD and Wang, JF and Aspnes, DE}, year={2002}, month={May} }
 @article{wang_powell_johnson_lucovsky_aspnes_2002, title={Simplified bond-hyperpolarizability model of second harmonic generation: Application to Si-dielectric interfaces}, volume={20}, ISSN={["2166-2746"]}, DOI={10.1116/1.1493783}, abstractNote={We show that the anisotropies of second-harmonic-generation (SHG) intensities of singular and vicinal (111) and (001)Si–dielectric interfaces can be described accurately as dipole radiation originating from the anharmonic motion of bond charges parallel to the bond directions. This simplified bond-hyperpolarizability model not only provides a simpler and mathematically more efficient representation of SHG, but also allows a direct physical interpretation at the bond level, which was lacking in previous approaches. Application to oxidized and nitrided Si–SiO2 interfaces provides new insight into bonding that occurs at these interfaces as well as the origin of SHG.}, number={4}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Wang, JFT and Powell, GD and Johnson, RS and Lucovsky, G and Aspnes, DE}, year={2002}, pages={1699–1705} }
 @article{edwards_madsen_robbie_powell_jarrendahl_cobet_esser_richter_aspnes_2000, title={Real-time assessment of overlayer removal on 4H-SiC surfaces: Techniques and relevance to contact formation}, volume={338-3}, ISBN={["*************"]}, ISSN={["0255-5476"]}, DOI={10.4028/www.scientific.net/msf.338-342.1033}, abstractNote={We applied real-time spectroscopic ellipsometric (SE) measurements to assess the removal of overlayer material from 4H-SiC Si- and C-face surfaces in order to investigate the final step of an other ...}, number={3}, journal={SILICON CARBIDE AND RELATED MATERIALS - 1999 PTS, 1 & 2}, author={Edwards, NV and Madsen, LD and Robbie, K and Powell, GD and Jarrendahl, K and Cobet, C and Esser, N and Richter, W and Aspnes, DE}, year={2000}, pages={1033–1036} }
 @misc{powell_2000, title={Teaching, propaganda, and the middle ground}, volume={53}, number={11}, journal={Physics Today}, author={Powell, G.}, year={2000}, pages={7878} }