Synthesis of titanium dioxide nanotubes for the development of betavoltaic cells

Abstract

In recent decades, nanotechnology has developed rapidly. Nanotechnology makes the basis for various microelectronic devices that use micro- or milliwatt power. Betavoltaic batteries can serve as power generators of such order. They are combined sets of betavoltaic cells (BVC) based on long-live isotopes and semiconductor converters. This paper considers the use of nickel-63 — an isotope with a half-life of 100.1 years and an average beta-particle energy of 17.4 keV – as a betaradiation source for single BVCs. The advantages of using nickel-63 include safety, technological adaptability, and purity. It emits soft beta-radiation, which does not create critical defects in semiconductors. Titanium dioxide, which is an n-type semiconductor and has high radiation resistance, was used as a semiconductor converter. Titanium dioxide has a relatively wide band gap (3.0 eV for anatase) and can easily develop its surface through common electrochemical anodizing process. The combination of developed structure and a wide band gap will increase the probability of creating a high power density BVC. The authors of this paper synthesized and modified the vertically aligned TiO2 nanotube arrays and used them to develop a slim prototype BVC using a 20% enriched nickel-63 isotope. Having the dimensions of 20 mm × 20 mm × (15–17) μm, the resulting BVC has an open-circuit voltage of 0.3 V and a short-circuit current density of 0.35 nA/cm2. Such electrical characteristics in combination with very small dimensions can potentially lead to the development of a betavoltaic battery with increased power density.The authors would like to thank Aleksey S. Shadskiy and German L. Ilyichev, who were first to engage in betavoltaic studies at Luch; Dmitry A. Zaytsev for conducting an X-ray phase analysis; Dmitry S. Kiselev for conducting a SEM study; Aleksandra A. Igonina for her su pport with preparation work; Ivan E. Galev and Andrey A. Mokrushin for their creativity and organizational support.This research was carried out as part of Rosatom’s Single Industry-Specific Plan: Developing a Radioisotope Power Module for Periodically Activated Electronic Devices.