Analysis of the attainable efficiency of a direct-bandgap betavoltaic element

• Published in: arXiv.org
• Main Authors: Sachenko, A V, Shkrebtii, A I, Korkishko, R M, Kostylyov, V P, Kulish, N P, Sokolovskiy, I O, Evstigneev, M
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 13.04.2015
• Subjects: Beta rays; Coefficients; Collection; Electrical junctions; Electrons; Energy conversion efficiency; Energy gap; Gallium arsenide; Holes (electron deficiencies); Minority carriers; Open circuit voltage; P-n junctions; Particle physics; Physics - Materials Science
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1504.03179

Conversion of energy of beta-particles into electric energy in a p-n junction based on direct-bandgap semiconductors, such as GaAs, considering realistic semiconductor system parameters is analyzed. An expression for the collection coefficient, \(Q\), of the electron-hole pairs generated by beta-electrons is derived taking into account the existence of the dead layer. We show that the collection coefficient of beta-electrons emitted by a \Tr-source to a GaAs p-n junction is close to 1 in a broad range of electron lifetimes in the junction, ranging from \(10^{-9}\) to \(10^{-7}\) s. For the combination \Pm/GaAs, \(Q\) is relatively large (\(\ge 0.4\)) only for quite long lifetimes (about \(10^{-7}\) s) and large thicknesses (about \(100\,\mu\)m) of GaAs p-n junctions. For realistic lifetimes of minority carriers and their diffusion coefficients, the open-circuit voltage realized due to the irradiation of a GaAs p-n junction by beta-particles is obtained. The attainable beta-conversion efficiency \(\eta\) in the case of a \Tr/GaAs combination is found to exceed that of the \Pm/GaAs combination.