Persistent room temperature photodarkening in Cu-doped \b{eta}-Ga2O3

Bibliographic Details
Title: Persistent room temperature photodarkening in Cu-doped \b{eta}-Ga2O3
Authors: Jesenovec, J., Pansegrau, C., McCluskey, M. D., McCloy, J. S., Gustafson, T. D., Halliburton, L. E., Varley, J. B.
Publication Year: 2022
Collection: Condensed Matter
Subject Terms: Condensed Matter - Materials Science
More Details: Beta-Ga2O3 is an ultra-wide bandgap semiconductor with emerging applications in power electronics. The introduction of acceptor dopants yields semi-insulating substrates necessary for thin-film devices. In the present work, exposure of Cu-doped Ga2O3 to UV light > 4 eV is shown to cause large, persistent photo-induced darkening at room temperature. Electron paramagnetic resonance spectroscopy indicates that light exposure converts Cu2+ to Cu3+, a rare oxidation state that is responsible for the optical absorption. The photodarkening is accompanied by the appearance of O-H vibrational modes in the infrared spectrum. Hybrid function calculations show that Cu acceptors can favorably complex with hydrogen donors incorporated as interstitial (Hi) or substitutional (H_O) defects. When Cu_Ga-H_O complexes absorb light, hydrogen is released, contributing to the observed Cu3+ species and O-H modes.
Document Type: Working Paper
DOI: 10.1103/PhysRevLett.128.077402
Access URL: http://arxiv.org/abs/2201.01861
Accession Number: edsarx.2201.01861
Database: arXiv
More Details
DOI:10.1103/PhysRevLett.128.077402