The Impact of Surface Chemistry on Photoelectrochemical Device Characteristics

Citation

Rosenberg, Robert Alan (2011) The Impact of Surface Chemistry on Photoelectrochemical Device Characteristics. Senior thesis (Major), California Institute of Technology. doi:10.7907/TW3G-C242. https://resolver.caltech.edu/CaltechTHESIS:06032011-161436489

Abstract

Varying degrees of partial methylation are performed on the (111) surface of p-type Si in order to investigate the role of mixed surface functionality on the device’s overall properties. Current-voltage characteristics are acquired in nonaqueous regenerative photoelectrochemical cells with a variety of one-electron redox species. P-type and p/n+ electrodes are evaluated, allowing comparisons between devices where the energy barrier is set by the semiconductor-liquid interface and devices where the energy barrier is set by the buried junction with the heavily doped emitter layer. In contrast to fully methylated or entirely unprotected surfaces, the intermediately methylated devices exhibit mixed monolayers with a disparity in barrier height. Charge transfer across these interfaces is studied, and effects such as pinch-off are considered in the search for a threshold surface composition for acceptable device performance.

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