Nanostructured Titanium Dioxide Modification Using the Hydrothermal Method to Enhance the Electrical Parameters of Betavoltaic Cells

Abstract

New technologies of microelectronics are emerging to reduce the size of devices and combine them into more compact ultralow power systems. Betavoltaic power sources (BVPSs) can serve as power generators of such order. BVPSs consist of a combination of betavoltaic cells (BVCs) based on long-lived radioisotopes of beta radiation and semiconductor converters (SCs). One of the key tasks for increasing the power of BVCs is the selection of SCs that can efficiently convert the energy of beta particles into electricity. Currently, semiconductor structures with a developed surface and a high band gap are considered to be perspective SCs. In present work, arrays of titanium dioxide nanopores (TiO₂ NPs) synthesized by common electrochemical anodization were chosen as a SCs. These SCs were part of BVCs based on nickel-63 with an activity of ~10 Ci/g. TiO₂ NPs with an amorphous structure in the composition of BVC demonstrated low electrical parameters. To increase them, we modified TiO₂ NPs by the hydrothermal method in a solution of Sr(OH)₂ with a concentration of 0.05 mol/L at various times. These experiments were carried out in order to convert TiO₂ (anatase) into structure-like SrTiO₃. We found that the electrical parameters of the SCs increased with the duration of the modification time. The best result was obtained in the case of modification for 3 h—the BVC generated a short circuit current of 2.9 nA and open circuit voltage of 0.8 V and had a maximum power of 0.8 nW at 0.45—0.5 V. The obtained electrical parameters in combination with the miniature dimensions of the BVCs open up the potential possibility of creating a BVPS with an increased power density.