| Charge transport measurements provide essential insight to many material properties and characteristics. Several different charge transport measurements, which include the Hall effect, electrical conductivity, and thermoelectric power were used to study two main types of materials: thermoelectric systems and transparent conducting oxides.; The transport characteristics are essential in evaluating the potential applications of new materials systems for thermoelectric performance by determining the figure of merit. Previous work on CsBi4Te6, identified this compound as the host material with the best thermoelectric performance below room temperature. New dopants and mixed compositions of this material have further improved the performance resulting in a higher figure of merit below room temperature.; Several different transparent conducting oxide materials were studied with transport measurements. Compounds of In2O3, SnO 2, and ZnO have been studied in the bulk and thin film form. In an effort to try to p dope these materials, excess Zn ions were introduced and the samples were oxidized. Other novel transparent conducting oxides studied were CdO thin films, which were found to have exceptional electrical properties. For all of the different transparent conducting oxide materials, variable temperature conductivity and Hall measurements were used to improve the operating characteristics of each material.; Organic field effect transistors were designed and the preliminary devices were produced and tested. Several different designs of the device structure have been studied. This project is an ongoing effort and with the initial designs and testing in place, a large scale study of novel organic materials as active regions is possible.; Charge transport measurements have been extremely useful to identify improvements in the figure of merit for thermoelectric materials below room temperature and have been equally as useful in the optimization of transparent conducting oxide materials to determine which have exceptional electrical properties. Although these material systems appear very different, they both have very large carrier concentrations and are very conductive which allows for interesting comparisons between the two material systems. |
