Performance study of GaN-based betavoltaic nuclear batteries with 3D interfaces

Area of Science:

• Materials Science
• Nuclear Engineering
• Semiconductor Physics

Background:

• Betavoltaic nuclear batteries offer long-term power solutions.
• Gallium Nitride (GaN) is a promising semiconductor for these devices.
• Optimizing 3D interface structures is crucial for performance.

Purpose of the Study:

• To design and simulate a 3D interface model for GaN-based betavoltaic batteries.
• To forecast battery performance using different radioactive sources and structural parameters.
• To compare the impact of practical machining processes on battery output.

Main Methods:

• Utilized Geant4 to compute electron-hole pair generation rates in GaN under ⁶³Ni and ¹⁴⁷Pm irradiation.
• Employed COMSOL Multiphysics for finite element analysis of electron-hole pair transport.
• Simulated the influence of structural parameters like inverted pyramid count and junction depth.

Main Results:

• Simulation revealed significant performance variations (J_sc, V_oc, P_max) with different radioactive sources.
• Optimized parameters (⁶³Ni source, specific doping, 0.1 μm junction depth, 25 inverted pyramids) yielded J_sc=0.648 μA/cm², V_oc=2.3481 V, P_max=1.2949 μW/cm².
• Switching to a ¹⁴⁷Pm source resulted in a substantial increase in J_sc to 56.865 μA/cm² and P_max to 94.975 μW/cm².

Conclusions:

• The choice of radioactive source critically impacts GaN betavoltaic battery performance.
• ¹⁴⁷Pm offers significantly higher output power density compared to ⁶³Ni.
• The 3D interface simulation model provides a valuable tool for optimizing betavoltaic device design.