title: Ultrafast Spectroscopy and Red Emission from β-Ga2O 3/β-Ga 2S 3 Nanowires.
abstract: Ultrafast pump-probe and transient photoluminescence spectroscopy were used to investigate carrier dynamics in β-Ga2O3 nanowires converted to β-Ga2O3/Ga2S3 under H2S between 400 to 600 °C. The β-Ga2O3 nanowires exhibited broad blue emission with a lifetime of 2.4 ns which was strongly suppressed after processing at 500-600 °C giving rise to red emission centered at 680 nm with a lifetime of 19 μs. Differential absorption spectroscopy reveals that state filling occurs in states located below the conduction band edge before sulfurization, but free carrier absorption is dominant in the β-Ga2O3/Ga2S3 nanowires processed at 500 to 600 °C for probing wavelengths >500 nm related to secondary excitation of the photo-generated carriers from the mid-gap states into the conduction band of Ga2S3.
authors.affiliation: Laboratory of Ultrafast Science, Department of Physics, University of Cyprus, PO Box 20537, Nicosia, 1678, Cyprus.
authors.forename: Katerina M
authors.initials: KM
authors.lastname: Othonos
authors.forename: Matthew
authors.initials: M
authors.lastname: Zervos
authors.forename: Constantinos
authors.initials: C
authors.lastname: Christofides
authors.forename: Andreas
authors.initials: A
authors.lastname: Othonos