Experimental and theoretical band alignment of Ta2O5/ZnO stack for heterostructured devices applications

Oxide semiconductor interfaces exhibit a promising expectation in electronic devices. The band alignment at the heterointerface plays a key role in determining the carrier transport and device performances. In this study, a Ta2O5/ZnO heterojunction is fabricated by using radio-frequency magnetron sputtering and ion beam sputtering technologies on a alpha-sapphire substrate. The energy-band offsets are determined by using the X-ray photoelectron spectroscopy and electron affinity rule. The heterojunction between Ta2O5 and ZnO shows a Type I band alignment accompanied with a conduction band offset of 0.33 +/- 0.03 eV and a valence band offset of -0.38 +/- 0.03 eV. In all, this work could provide an indication for their heterostructured devices fabrications, owing to its large conduction band offset and excellent electron confinement across the heterointerface of Ta2O5/ZnO.

Automated summary

In this study, a Ta2O5/ZnO heterojunction was fabricated and the energy-band offsets were determined by X-ray photoelectron spectroscopy and electron affinity rule. The results showed a Type I band alignment with a conduction band offset of 0.33 +/- 0.03 eV and a valence band offset of -0.38 +/- 0.03 eV, indicating potential for heterostructured devices fabrication with excellent electron confinement.