Κ-Ga2O3/GaN ferroelectric/polar semiconductor heterojunction for high electron mobility transistors

Polar semiconductor heterostructures offer an alternative strategy to manipulate polarization towards advanced devices with engineered functionality and improved performance. Recently, Prof. Jiandong Ye's group from Nanjing University reported on a novel kappa-Ga2O3/GaN ferroelectric/polar heterojunction with switchable polarization under external electric field. A type-II band alignment is determined at the kappa-Ga2O3/GaN polar hetero-interface, with charge dipoles induced by spontaneous polarization leading to the observed band bending. Benefiting from the large band discontinuity and ferroelectric manipulation, it is expected to realize the switching of the interfacial two-dimensional electron gas between accumulation and depletion states, which allows the rational design of kappa-Ga2O3 ferroelectric/polar heterojunctions for the application of high electron mobility transistors, ferroelectric non-volatile memories and even ultra-low loss negative capacitance transistors.