ABSTRACT
Herein, we find that TiN sputter-deposited on GaN displayed the desired optical properties for plasmonic applications. While this is a positive result indicating the possible use of p- or n-type GaN as a collector of plasmonically generated hot carriers, the interfacial properties differed considerably depending on doping conditions. On p-type GaN, a distinct Schottky barrier was formed with a barrier height of ~0.56 eV, which will enable effective separation of photogenerated electrons and holes, a typical approach used to extend their lifetimes. On the other hand, no transport barrier was found for TiN on n-type GaN. While the lack of spontaneous carrier separation in this system will likely reduce unprompted hot carrier collection efficiencies, it enables a bias-dependent response whereby charges of the desired type (e.g., electrons) could be directed into the semiconductor or sequestered in the plasmonic material. The specific application of interest would determine which of these conditions is most desirable.
ABSTRACT
Betavoltaic power sources based on the conversion of radioisotope energy to electrical power are considered an appealing option for remote applications due to extended period of operation and high energy densities. However, to be competitive with other power sources, their efficiency must be increased. This can be done through optimization of the beta source and selection of the semiconductor absorber. This paper evaluates available on the market and developing wideband gap semiconductors as prospective absorbers with 3H and 63Ni sources. Simulation results indicate that among wide band gap materials 4H-SiC and diamond are two optimal semiconductors due to the combination of good coupling efficiencies with isotope sources and good electronic transport properties. Additionally, having good coupling efficiency, an ultra-wide bandgap, and the capability for both n- and p-type doping, c-BN is a promising material for betavoltaic applications.
