Origin of the self-limited electron densities at Al2O3/SrTiO3 heterostructures grown by atomic layer deposition – oxygen diffusion model

Recently, 2-dimensional electron gas (2-DEG) was discovered at the interface of Al2O3/SrTiO3 (STO) heterostructures, in which the amorphous Al2O3 layers were grown by atomic layer deposition (ALD). The saturated electron density at the Al2O3/STO heterostructures above the critical thickness of Al2O3 is explained by an oxygen diffusion mechanism.