Design of High-Efficiency SiC Betavoltaic Battery Structures With Reduced Impact of Near-Surface Recombination Based on Accurate Modeling

Combined with the actual parameters of silicon carbide (SiC), an accurate numerical model is established to predict the energy conversion efficiency ( \eta_{\textit{c}} ) of the semiconductor conversion device in Ti ^{\text{3}} H _{\text{2}} \vphantom{^{\int}} and ^{\text{63}} Ni betavoltaic batteries with an error of less than 1%. Based on accurate simulations, novel p-i-n diodes with thinned p-type region (TP), named TP p-i-n, and with passivation layer surface field (PLSF), named PLSF p-i-n, are proposed as semiconductor conversion devices in this article. The introduction of TP and PLSF reduces the proportion of p-type region with high Shockley-Read-Hall (SHR) recombination and the electron concentration near the surface, thereby reducing SRH and surface recombination loss. The simulation results show that, under different minority carrier diffusion length ( \textit{L}_{\textit{n}} ) and surface recombination velocity ( \textit{S} ) of p-type region, that is, under different material qualities represented by \textit{S} and \textit{L}_{\textit{n}} , compared with the conventional p-i-n diode (Cov. p-i-n), \eta_{\textit{c}} of TP p-i-n increases by a maximum of 110.7% and 13.3% for Ti ^{\text{3}} H _{\text{2}} and ^{\text{63}} Ni, respectively, and as for PLSF p-i-n are of 134.3% and 15.3%. As a result, when the material quality represented by \textit{S} and \textit{L}_{\textit{n}} deteriorates,