Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Physics
Time-Resolved Thz Conductivity Of An Intermediate Band Semiconductor, Elliot Weiss
Time-Resolved Thz Conductivity Of An Intermediate Band Semiconductor, Elliot Weiss
Macalester Journal of Physics and Astronomy
Intermediate band materials have promising applications as affordable, highly efficient solar materials. However, intermediate band solar cells exhibit low efficiency to date. Carrier recombination is a critical process that limits efficiency. If electrons relax to the valence band before they can be collected, their energy is lost. To help understand the recombination dynamics and physical properties of intermediate band semiconductors, we obtain time-resolved THz conductivity measurements of the intermediate band semiconductor, GaPAsN, at various temperatures. From our results, we build a model that provides insight to the recombination dynamics of GaPAsN.
Intervalley Scattering Rates In Tellurium Observed Via Time-Resolved Terahertz Spectroscopy, Joshua R. Rollag
Intervalley Scattering Rates In Tellurium Observed Via Time-Resolved Terahertz Spectroscopy, Joshua R. Rollag
Macalester Journal of Physics and Astronomy
We conducted time-resolved terahertz spectroscopy measurements on the elemental semiconductor tellurium. Pump-probe measurements were used to find the conductivity as a function of time in single crystalline tellurium samples. It was found that the excitation dynamics in tellurium changes for photon energies of 1.03 eV and 1.55 eV. The change in these excitation dynamics was attributed to intervalley scattering effects. A model using intervalley scattering and Auger recombination was fit to the data, giving a value of 2.28 ps for the intervalley scattering time constant in tellurium.
Conductivity Measurements Of A Thermoelectric Nanomaterial Through Thz Spectroscopy, Michaela S. Koller, James Heyman, Gunnar Footh
Conductivity Measurements Of A Thermoelectric Nanomaterial Through Thz Spectroscopy, Michaela S. Koller, James Heyman, Gunnar Footh
Macalester Journal of Physics and Astronomy
In today’s society there is a great demand on energy output—in the United States alone we rely heavily on non-renewable energy sources. Thermoelectric materials may be able to be used to create more efficient energy systems or recover wasted heat from inefficient technologies. This paper focuses on the conductivity of a new thermoelectric material that incorporates copper into a tellurium nanowire PEDOT:PSS material. The addition of copper seems to increase the conductivity of the material, although the exact relationship between the percentage of copper to tellurium and its affect on the conductivity is uncertain from the results.