Thin Ga2O3 Layers by Thermal Oxidation of van der Waals GaSe Nanostructures for Ultraviolet Photon Sensing

Cottam, Nathan D.; Dewes, Benjamin T.; Shiffa, Mustaqeem; Cheng, Tin S.; Novikov, Sergei V.; Mellor, Christopher J.; Makarovsky, Oleg; Gonzalez, David; Ben, Teresa; Patanè, Amalia

Abstract

Two-dimensional semiconductors (2DSEM) based on van der Waals crystals offer important avenues for nanotechnologies beyond the constraints of Moore's law and traditional semiconductors, such as silicon (Si). However, their application necessitates precise engineering of material properties and scalable manufacturing processes. The ability to oxidize Si to form silicon dioxide (SiO2) was crucial for the adoption of Si in modern technologies. Here, we report on the thermal oxidation of the 2DSEM gallium selenide (GaSe). The nanometre-thick layers are grown by molecular beam epitaxy on transparent sapphire (Al2O3) and feature a centro-symmetric polymorph of GaSe. Thermal annealing of the layers in an oxygen-rich environment promotes the chemical transformation and full conversion of GaSe into a thin layer of crystalline Ga2O3, paralleled by the formation of coherent Ga2O3/Al2O3 interfaces. Versatile functionalities are demonstrated in photon sensors based on GaSe and Ga2O3, ranging from electrical insulation to unfiltered deep ultraviolet optoelectronics, unlocking the technological potential of GaSe nanostructures and their amorphous and crystalline oxides.

Citation

Cottam, N. D., Dewes, B. T., Shiffa, M., Cheng, T. S., Novikov, S. V., Mellor, C. J., Makarovsky, O., Gonzalez, D., Ben, T., & Patanè, A. (2024). Thin Ga2O3 Layers by Thermal Oxidation of van der Waals GaSe Nanostructures for Ultraviolet Photon Sensing. ACS Applied Nano Materials, 7(15), 17553-17560. https://doi.org/10.1021/acsanm.4c02685

• Journal Article Type: Article
• Acceptance Date: Jul 22, 2024
• Online Publication Date: Jul 31, 2024
• Publication Date: Aug 9, 2024
• Deposit Date: Jul 24, 2024
• Publicly Available Date: Jul 24, 2024
• Journal: ACS Applied Nano Materials
• Print ISSN: 2574-0970
• Electronic ISSN: 2574-0970
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 15
• Pages: 17553-17560
• DOI: https://doi.org/10.1021/acsanm.4c02685
• Keywords: gallium selenide; van der Waals crystals; gallium oxide; oxidation; UV-photonics
• Public URL: https://nottingham-repository.worktribe.com/output/37595613
• Publisher URL: https://pubs.acs.org/doi/10.1021/acsanm.4c02685