Author ORCID Identifier

Document Type


Date of Award


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Dongming Mei


This dissertation focuses on the enhancement of crystal quality in High Purity Germanium (HPGe) detectors, which play a crucial role in rare-event physics investigations such as dark matter detection, neutrinoless double-beta decay, geo-neutrinos, and solar neutrinos. The primary objective of this research is to improve crystal quality by controlling impurity concentration, dislocation density, and growth environment. Additionally, the development of advanced Ge detectors for various physics applications is explored. One significant aspect examined in this dissertation is the investigation of systematic errors associated with the Hall effect system. The goal is to identify a reliable technique that minimizes the systematic error to only a few percent from the Hall Effect measurements. Three different van der Pauw geometries are studied, and their results are compared with each other. The dissertation also delves into the study of charge trapping, charge carrier transport, and impact ionization. Furthermore, the phenomenon of charge trapping in a p-type HPGe detector operated at 5.2 K is discussed in detail. The findings reveal a binding energy of approximately 5-8 meV at 5.2 K, indicating the detector’s suitability for detecting low-mass dark matter. In summary, this dissertation focuses on the improvement of crystal quality, the characterization of HPGe crystals, and the study of charge-trapping phenomena in a p-type HPGe detector. The outcomes of this research significantly contribute to the advancement of detector performance in rare-event physics studies.

Subject Categories



Crystal Growth, Crystallographic Orientation, Detector Characterization, Detector Fabrication, Sample Characterization, Zone refining

Number of Pages



University of South Dakota

Included in

Physics Commons



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