Controlling the electronic interface properties of AlO x / SrTiO 3 heterostructures

Depositing disordered Al on top of $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$ is a cheap and easy way to create a two-dimensional electron system in the $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$ surface layers. To facilitate future device applications, we passivate the heterostructure by a disordered $\mathrm{La}\mathrm{Al}{\mathrm{O}}_{3}$ capping layer to study the electronic properties by complementary x-ray photoemission spectroscopy and transport measurements on the very same samples. We also tune the electronic interface properties by adjusting the oxygen pressure during film growth.