Light-driven permanent transition of undoped Ga2O3 from insulator to conductor

Farida Selim

doi:10.1117/12.3023618

16 March 2024 Light-driven permanent transition of undoped Ga₂O₃ from insulator to conductor

Farida Selim

Proceedings Volume PC12887, Oxide-based Materials and Devices XV; PC1288708 (2024) https://doi.org/10.1117/12.3023618
Event: SPIE OPTO, 2024, San Francisco, California, United States

Abstract

The position of the localized states in the band gap often dictates the electrical and optical properties of wide band gap materials. Here we show that modulating the position of these states by external stimuli provide interesting ways to tailor the electrical properties of Ga2O3. Experiments showed that limited exposure to sub-bandgap light caused a permanent transition from an insulator state to a conductor state in an insulating Ga2O3 crystal with 9-orders of magnitude increase in electronic conduction. Photoexcitation by light induced modification in the charge state of defects and subsequent lattice distortion around them was shown to be the underlying mechanism behind this transition. Density functional theory calculations confirmed that modifying the charge state of defects lead to redistribution of the localized electrons and massive structural distortion in the lattice around them causing large shift in the density of states and introducing new states with shallower energy levels. Other examples on modulating the localized states such as hydrogen incorporation in vacancies will be discussed. Lastly a new spectroscopy method we recently developed to facilitate the measurement of the position and density of the localized states in the band gap will be presented.

Conference Presentation

Citation Download Citation

Farida Selim "Light-driven permanent transition of undoped Ga₂O₃ from insulator to conductor", Proc. SPIE PC12887, Oxide-based Materials and Devices XV, PC1288708 (16 March 2024); https://doi.org/10.1117/12.3023618

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