UC Santa Cruz

Photoconductive materials have become increasingly important for high-resolution radiation detectors because of their ability to directly or indirectly convert ionizing radiation into electrical signals. Optimizing material properties, device architectures, and fabrication processes is essential for developing next-generation imaging detectors with improved sensitivity, image quality, and reliability.This thesis investigates the fabrication, characterization, and optimization of photoconductive detector materials for radiation imaging applications. First, the effect of interrupting the deposition process during thick-film fabrication is systematically evaluated through electrical and optical characterization, including carrier transport, dark current, quantum conversion efficiency, and temporal response measurements. The results demonstrate that interrupting the deposition process does not significantly degrade detector performance, providing a practical approach for fabricating thicker photoconductive layers required for high-efficiency radiation detection.The second part of this work explores interface engineering through the investigation of multiple carrier-blocking layer materials to improve detector performance. Their effects on leakage current, charge collection efficiency, temporal response, and large-area device fabrication are systematically compared. The study identifies interface designs that effectively suppress charge injection while maintaining high photo conductive performance and demonstrates their compatibility with large-area detector fabrication.Finally, the influence of material oxidation on structural, chemical, and optoelectronic properties is investigated using complementary materials characterization techniques and correlated with device performance. The results provide insight into degradation mechanisms affecting detector stability and long-term reliability.Overall, this work advances the understanding of photoconductive radiation detectors by establishing practical fabrication strategies, optimizing interface engineering, and identifying material degradation mechanisms. These findings provide important design guidelines for the development of next-generation high-resolution imaging detectors for medical imaging and related radiation detection applications.