Evaluating suitable semiconducting materials for cryogenic power electronics.

The interest in hybrid electric aircraft has invigorated research into superconducting power networks and superconducting electrical machines. Underpinning this is the ability to control the flow of electrical current at cryogenic temperatures, using power electronic devices. The authors have, for the first time, directly compared the performance of technologically relevant semiconductor materials for the realisation of high-performance cryogenic power devices using a bulk resistivity model. By validating the model using both computational and experimental results, the performance of technologically relevant semiconductors has been calculated down to a temperature of 20 K where the freeze out of dopants is shown to be the major limiting factor in determining the performance of power electronic devices. Both Ge and GaAs are predicted to have a superior conductivity in comparison to the industrial standards Si and 4H-SiC due to greater carrier mobilities and lower dopant ionisation energies