Ultrafast Spectroscopy and Red Emission from β-Ga2O3/β-Ga2S3 Nanowires

Abstract

Ultrafast pump-probe and transient photoluminescence spectroscopy were used to investigate carrier dynamics in β-Ga 2 O 3 nanowires converted to β-Ga 2 O 3 /Ga 2 S 3 under H 2 S between 400 to 600°C. The β-Ga 2 O 3 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-Ga 2 O 3 /Ga 2 S 3 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 Ga 2 S 3 .

Fractal aluminum Cayley-trees to design plasmonic ultraviolet photodetectors

“…Long carrier lifetime avoids immediate recombination of electrons and holes, hence, provides generation of large photocurrent. In contrast, the carrier lifetime and recombination process for UV-compatible Ga 2 O 3 is in the range of a few nanoseconds (2.4 ns [25]). In this regime, noticeably short transition time is necessary to overcome the immediate recombination of the carriers.…”

Polymorphic Ga2S3 nanowires: phase-controlled growth and crystal structure calculations

“…20 The synthesis of a 0 -Ga 2 S 3 NWs has been demonstrated using various methods, including chemical vapor deposition (CVD) and sulfurization of Ga 2 O 3 NWs pre-synthesized by CVD or hydrothermal reaction. [21][22][23][24][25] The Sutter group synthesized g-Ga 2 S 3 nanotubes by sulfurization of GaAs NWs. 26 Since graphene-like two-dimensional (2D) layered materials have attracted much attention, the existence of 2D hexagonal crystal structures of Ga 2 S 3 was theoretically predicted.…”

Thermal Vapor Sulfurization of Ultrathin GaAs Layers on Sapphire Substrates Prepared by Direct Growth and Lift-Off and Transfer

“…For example, Ga 2 S 3 , having a direct bandgap of ∼3.4 eV, exhibits high secondary-harmonic-generation efficiency and large laser-induced-damage threshold as well. [7][8][9][10][11][12][13] These characteristics make M 2 E 3 potential candidates for applications in optical switching devices, photovoltaic, and high power and/or high efficiency nonlinear optics. [11][12][13][14] One of the most important issues is to grow the group-III chalcogenide thin films with controllable crystal structures that can be compatibly integrated with mature semiconductor and/or optical devices.…”

“…[7][8][9][10][11][12][13] These characteristics make M 2 E 3 potential candidates for applications in optical switching devices, photovoltaic, and high power and/or high efficiency nonlinear optics. [11][12][13][14] One of the most important issues is to grow the group-III chalcogenide thin films with controllable crystal structures that can be compatibly integrated with mature semiconductor and/or optical devices. 4,5,[10][11][12][13][14] Our recent studies revealed that Ga 2 S 3 thin films can be epitaxially synthesized on epiready GaAs (111) substrates via thermal vapor sulfurizations (TVS), however, their phase structures are strongly depended on the sulfurization conditions and durations.…”

“…[11][12][13][14] One of the most important issues is to grow the group-III chalcogenide thin films with controllable crystal structures that can be compatibly integrated with mature semiconductor and/or optical devices. 4,5,[10][11][12][13][14] Our recent studies revealed that Ga 2 S 3 thin films can be epitaxially synthesized on epiready GaAs (111) substrates via thermal vapor sulfurizations (TVS), however, their phase structures are strongly depended on the sulfurization conditions and durations. 9,10 In addition, the relatively small bandgap of the GaAs substrate limits the applications of the epitaxially grown Ga 2 S 3 , typically for nonlinear optics in the visible frequency range.…”