Band alignment and polarization engineering in κ-Ga2O3/GaN ferroelectric heterojunction

Ferroelectric-semiconductor heterostructures offer an alternative strategy to manipulate polarization towards advanced devices with engineered functionality and improved performance. In this work, we report on the heteroepitaxial construction, band structure alignment and polarization engineering of the single-phased kappa-Ga2O3/GaN ferroelectric/polar heterojunction. A type-II band alignment is determined at the kappa-Ga2O3/GaN polar hetero-interface, with a valence band offset of (1.74 +/- 0.1) eV and a conduction band offset of (0.29 -/+ 0.1) eV Besides the band edge discontinuity, charge dipoles induced by spontaneous polarization lead to the observed band bending with built-in potentials of 0.9 and 0.33 eV, respectively, at the kappa-Ga2O3 surface and kappa-Ga2O3/GaN interface. The polarization switching properties of ferroelectric kappa-Ga2O3 are identified with a remanent polarization of approximately 2.7 mu C/cm(2) via the direct hysteresis remanent polarization/voltage (P-V) loop measurement. These findings allow the rational design of kappa-Ga2O3 ferroelectric/polar heterojunction for the application of power electronic devices, advanced memories and even ultra-low loss negative capacitance transistors.

Automated summary

Ferroelectric-semiconductor heterostructures provide an alternative strategy for manipulating polarization towards advanced devices. This work focuses on the heteroepitaxial construction, band structure alignment, and polarization engineering of the kappa-Ga2O3/GaN ferroelectric/polar heterojunction. The findings of this study have implications for the rational design of ferroelectric/polar heterojunctions for applications in power electronic devices, advanced memories, and ultra-low loss negative capacitance transistors.