Direct energy conversion using Ni/SiC Schottky junction in ²³⁷Np and ²⁴¹Am gamma ray regions

Direct energy conversion has been investigated using Ni/SiC Schottky junctions with the irradiation of monochromatized synchrotron x rays mimicking the gamma rays of ²³⁷Np (30 keV) and ²⁴¹Am (60 keV). Through current–voltage measurements, electrical energies were obtained for both types of gamma rays. The energy conversion efficiencies based on absorbed energy were found to be ∼1.6%, which is comparable to other previously described semiconducting systems. This result raises the prospect of energy recovery from nuclear wastes utilizing the present system, judging from the radiation tolerant nature of SiC. Additionally, we found different conversion efficiencies between the two samples during the same process. This could be explained using hard x-ray photoelectron spectroscopy and secondary ion mass spectroscopy measurements, suggesting the creation of Ni–Si compounds at the interface in the sample with poor performance. Hence, such combined measurements are useful to provide data that electrical measurements cannot provide us.