<p> This thesis presents an investigation of the electron-voltaic effect using epitaxial P-N junctions. The effect is manifested in the direct energy conversion of beta particles emitted from a radioisotope promethium^147 source by single and multi-junction devices. The purpose of the investigation is to determine the power outputs of the devices which may be combined in series and parallel combinations in the construction of an atomic battery with a small size and long lifetime (approximately 5 -10 years). </p> / Thesis / Master of Science (MSc)