Roles of core-shell and {delta}-ray kinetics in layered BN {alpha}-voltaic efficiency

Journal Article · Thu Feb 14 00:00:00 EST 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4790506· OSTI ID:22102267

Melnick, Corey ^[1]; Kaviany, Massoud ^[1]; Kim, Moo-Hwan ^[2]

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1. Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109 (United States)
2. Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of)

{alpha}-voltaics harvest electron-hole pairs created as energetic {alpha} particles collide with and ionize electrons in a semiconductor, creating {delta}-rays. After ionization, charged pair production continues through {delta}-ray impact ionization events and the Auger relaxation of core-shell holes created through K-shell ionization events. Secondary ionization events are quantified using the TPP-2M model, the fraction of K-shell ionization events is determined using the energy-loss Coulomb-repulsion perturbed-stationary-state relativistic theory, and the relaxation of the resulting holes is treated with a fully ab initio approach using multiple Fermi golden rule calculations for ranges of carrier concentrations and temperatures. The limiting rate is 15 ns{sup -1} for small carrier concentrations and high temperatures, as compared to the radiative core-shell relaxation rate estimated here at 20 ns{sup -1}, indicating that Auger modes contribute significantly. Moreover, the K-shell ionization events are shown to dominate for low energy {alpha} particles and vanish for high energy ones. Thus, the efficiency loss due to energy dissipation in the fuel layer is mitigated, which is demonstrated by the analysis of a layered fuel-voltaic device with an efficiency from 20% to 14% for fuel layers between 5 and 10 {mu}m thick. The design of a {alpha}-voltaic integrated with a thermoelectric generator is suggested for improved efficiency and the system-level mitigation of radiation damage and geometric inefficiency.

• OSTI ID: 22102267
• Journal Information: Journal of Applied Physics, Vol. 113, Issue 6; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALPHA PARTICLES
AUGER EFFECT
BORON NITRIDES
COULOMB FIELD
EFFICIENCY
ELECTRON-HOLE COUPLING
ENERGY LOSSES
IONIZATION
K SHELL
LAYERS
MITIGATION
PAIR PRODUCTION
PHYSICAL RADIATION EFFECTS
RELATIVISTIC RANGE
RELAXATION
SEMICONDUCTOR MATERIALS
THERMOELECTRIC GENERATORS