Optimization design of GaAs-based betavoltaic batteries with p–n junction and Schottky barrier structures

Abstract This paper presents the calculation model and the optimization design of the GaAs-based betavoltaic batteries with p–n junction and Schottky barrier structures. First of all, by using the Monte Carlo code, the transport process and energy deposition distribution of the 63 Ni source beta particles in the GaAs material are simulated. The relationships between the output parameters of batteries and the physical parameters of energy converter such as p–n junction depth, Schottky metal thickness, depletion region width and doping concentrations are discussed through the numerical calculation. For the GaAs p–n junction battery, the maximum output power density of 0.135 μ W cm − 2 can be achieved when the junction depth is x j = 0.05 μ m , the doping concentrations are N a = 10 18 cm − 3 and N d = 2 × 10 15 cm − 3 . Meanwhile, the short-circuit current density, open-circuit voltage, filling factor and energy conversion efficiency are 0.254 μ A cm − 2 , 0.638 V, 83.3% and 2.63%, respectively. Among the selected metals of Au, Pd, Ni and Pt for the GaAs Schottky barrier diodes, the Pt-GaAs battery has the best output performance due to its large work function. The maximum output power density of 0.169 μ W cm − 2 can be achieved when a 20 nm thick Schottky metal Pt is selected and the doping concentration is N d = 10 15 cm − 3 . The associated output parameters of the battery are 0.234 μ A cm − 2 , 0.835 V, 86.5% and 3.29%, respectively.