Direct energy conversion using Ni/SiC Schottky junction in Np and Am gamma ray regions

Fukuda, Tatsuo  ; Kobata, Masaaki  ; Shobu, Takahisa  ; Yoshii, Kenji  ; Kamiya, Junichiro   ; Iwamoto, Yosuke   ; Makino, Takahiro*; Yamazaki, Yuichi*; Oshima, Takeshi*; Shirai, Yasuhiro*; Yaita, Tsuyoshi

Direct energy conversion has been investigated using Ni/SiC Schottky junctions with the irradiation of monochromatized synchrotron X-rays simulating the gamma rays of Np (30 keV) and Am (60 keV). From current-voltage measurements, electrical energies were obtained for both kinds of gamma rays. The energy conversion efficiencies were found to reach up to 1.6%, which is comparable to those of a few other semiconducting systems reported thus far. This result shows a possibility of energy recovery from nuclear wastes using the present system, judging from the radiation tolerant nature of SiC. Also, we found different conversion efficiencies between the two samples. This could be understandable from hard X-ray photoelectron spectroscopy and secondary ion mass spectroscopy measurements, suggesting the formation of Ni-Si compounds at the interface in the sample with a poor performance. Hence, such combined measurements are useful to provide information that cannot be obtained by electrical measurements alone.