Enhancement of Open Circuit Voltage of Diamond Voltaic Battery by Surface Passivation

Nuclear batteries based on the voltaic effect using Schottky diode or p-n junction energy converter are usually named alpha-/beta-voltaic batteries. They present particularly unique properties, making them highly interesting in many key technological applications. Diamond exhibits great potential in designing such high performance alpha-/beta-voltaic batteries and self-powered UV detectors. In this study, we present a novel strategy to create highly efficient diamond Schottky diodes. Our approach consists of incorporating a thin TiO2 layer in the vertical diamond Schottky diode using reactive magnetron sputtering to enhance the barrier height and improve the voltaic performance. Thermionic emission (TE) theory was used to extract the Schottky barrier heights. The extracted value of the improved diode was in good agreement with the Schottky-Mott model. The high open circuit voltages of 1.7 and 1.8 V were obtained using americium-241 and deuterium lamp illumination. The short circuit current density was much higher than device without a TiO2 layer.