3D GaN-based betavoltaic device design with high energy transfer efficiency.

A combined GaN 3D core-shell and planar pin structure is being developed and demonstrated to achieve the highest potential to increase energy transfer efficiency from the source (η) and power generated per cm (P/cm) in a betavoltaic (BV) device configuration. Physics-based Sentaurus TCAD and Monte Carlo N-Particle extended (MCNPX) software are employed to obtain the maximum η and P/cm by a parametric study of device dimensions coupled with a NiCl source. Idealized structure dimensions are determined to be 2 µm wide, 4 µm tall GaN pin core-shell mesas, with Ni source conformally surrounding the structure with a 2 µm gap for maximum efficiency of energy transfer.

Demonstration of a Tritiated Nitroxide Nuclear Battery.

Unattended, compact, terrestrial and space sensors require sources that have high energy and power densities to continuously operate for 3 to 99 years depending on application. Currently, chemical sources cannot fully satisfy these applications, especially in solid state form. Betavoltaic (βV) nuclear batteries using β-emitting radioisotopes possess energy densities 1000 times greater than conventional chemical sources.

A radioluminescent nuclear battery using volumetric configuration: Ni solution/ZnS:Cu,Al/InGaP.

Energy dense power sources are critical to the development of compact, remote sensors for terrestrial and space applications. Nuclear batteries using β-emitting radioisotopes possess energy densities 1000 times greater than chemical batteries. Their power generation is a function of β flux saturation point relative to the planar (2D) configuration, β range, and semiconductor converter.

Development of tritiated nitroxide for nuclear battery.

Beta radioisotope energy sources, such as tritium (H), have shown significant potential in satisfying the needs of a sensor-driven world. The limitations of current beta sources include: (i) low beta-flux power, (ii) intrinsic isotope leakage and (iii) beta self-absorption. The figure of merit is the beta-flux power (dP/dS in μW/cm), where an optimal portion of incident beta particles penetrates the semiconductor depletion region.