Growth and characterization of gallium oxide films grown with nitrogen by plasma-assisted molecular-beam epitaxy

Ngo, Trong Si; Le, Duc C.; Song, Jung-Hoon; Hong, Seungwoo

doi:10.1016/j.tsf.2019.05.029

Cited by 23 publications

(11 citation statements)

References 41 publications

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“…The dissociation of the N 2 anion in the 2D Ga 2 O 3 film considerably altered its energy bandgap. The origin of the decreased bandgap is attributed to the N acceptor states [30][31][32] in the bandgap of Ga 2 O 3 . Therefore, N 2 -doped Ga 2 O 3 is considered a valuable candidate for tunable optoelectronic applications and can also affect the charge transfer mechanism at hetero-interfaces.…”

Section: Thin Film Characterizationmentioning

confidence: 98%

Nano-engineering and functionalization of hybrid Au–Me_xO_y–TiO₂(Me = W, Ga) hetero-interfaces for optoelectronic receptors and nociceptors

Akbari

Verpoort

et al. 2020

Nanoscale

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Section: Thin Film Characterizationmentioning

confidence: 98%

Nano-engineering and functionalization of hybrid Au–Me_xO_y–TiO₂(Me = W, Ga) hetero-interfaces for optoelectronic receptors and nociceptors

Akbari

Verpoort

et al. 2020

Nanoscale

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“…This implies that the introduction of ionic nitrogen into Ga 2 O 3 considerably altered its band structure. The origin of the decreased bandgap was attributed to the N acceptor states in the bandgap of Ga 2 O 3 [ 16 – 18 ]. The other evidences about bandgap alteration of nitrogen-doped ultra-thin Ga 2 O 3 film are discussed in the next section.…”

Section: Resultsmentioning

confidence: 99%

“…The origin of the decreased bandgap was attributed to the N acceptor states in the bandgap of Ga 2 O 3 [16][17][18]. The other evidences about bandgap alteration of nitrogen-doped ultrathin Ga 2 O 3 film are discussed in the next section.…”

Section: Structural Propertiesmentioning

confidence: 95%

Nanoscale All-Oxide-Heterostructured Bio-inspired Optoresponsive Nociceptor

Akbari

Verpoort

et al. 2020

Nano-Micro Lett.

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HIGHLIGHTS • Artificial optoelectronic nociceptor based on two-dimensional heterostructured all-oxide nanostructures was designed. • Two-dimensional heterointerfaces were functionalized, and their engineering toward fabrication of artificial nociceptors was confirmed. ABSTRACT Retina nociceptor, as a key sensory receptor, not only enables the transport of warning signals to the human central nervous system upon its exposure to noxious stimuli, but also triggers the motor response that minimizes potential sensitization. In this study, the capability of two-dimensional all-oxide-heterostructured artificial nociceptor as a single device with tunable properties was confirmed. Newly designed nociceptors utilize ultra-thin sub-stoichiometric TiO 2-Ga 2 O 3 heterostructures, where the thermally annealed Ga 2 O 3 films play the role of charge transfer controlling component. It is discovered that the phase transformation in Ga 2 O 3 is accompanied by substantial jump in conductivity, induced by thermally assisted internal redox reaction of Ga 2 O 3 nanostructure during annealing. It is also experimentally confirmed that the charge transfer in alloxide heterostructures can be tuned and controlled by the heterointerfaces manipulation. Results demonstrate that the engineering of heterointerfaces of two-dimensional (2D) films enables the fabrication of either high-sensitive TiO 2-Ga 2 O 3 (Ar) or high-threshold TiO 2-Ga 2 O 3 (N 2) nociceptors. The hypersensitive nociceptor mimics the functionalities of corneal nociceptors of human eye, whereas the delayed reaction of nociceptor is similar to high-threshold nociceptive characteristics of human sensory system. The long-term stability of 2D nociceptors demonstrates the capability of heterointerfaces engineering for effective control of charge transfer at 2D heterostructured devices.

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“…It was noticed that the KA100 samples comprising of A-R phases have an energy bandgap between 3.06 and 3.03 eV. Keeping in mind that the bandgap of a semiconductor can be influenced by several factors such as doping, synthetic parameters, lattice mismatch [ 46 ], crystallite size [ 47 ], annealing/calcination temperature [ 48 ], and phase composition, and also based on the recent reports that inform “the bandgap determination through extrapolation of Tauc segment to the hv (X) axis is not appropriate for samples containing more than one prominent optical absorbing center/or phase” [ 49 , 50 ], the bandgap was also determined the by extrapolation of the linear part of the dependence to the baseline ( Figure 2 ). The optical band as determined by the Tauc plot and baseline extrapolation method is referred to as BG-T and BG-BE, respectively.…”

Section: Resultsmentioning

confidence: 99%

Cost-Effective Production of TiO2 with 90-Fold Enhanced Photocatalytic Activity Via Facile Sequential Calcination and Ball Milling Post-Treatment Strategy

et al. 2020

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Titanium dioxide (TiO2), the golden standard among the photocatalysts, exhibits a varying level of photocatalytic activities (PCA) amongst the synthetically prepared and commercially available products. For commercial applications, superior photoactivity and cost-effectiveness are the two main factors to be reckoned with. This study presents the development of simple, cost-effective post-treatment processes for a less costly TiO2 to significantly enhance the PCA to the level of expensive commercial TiO2 having demonstrated superior photoactivities. We have utilized sequential calcination and ball milling (BM) post-treatment processes on a less-costlier KA100 TiO2 and demonstrated multi-fold (nearly 90 times) enhancement in PCA. The post-treated KA100 samples along with reference commercial samples (P25, NP400, and ST01) were well-characterized by appropriate instrumentation and evaluated for the PCA considering acetaldehyde photodegradation as the model reaction. Lattice parameters, phase composition, crystallite size, surface functionalities, titanium, and oxygen electronic environments were evaluated. Among post-treated KA100, the sample that is subjected to sequential 700 °C calcination and BM (KA7-BM) processes exhibited 90-fold PCA enhancement over pristine KA100 and the PCA-like commercial NP400 (pure anatase-based TiO2). Based on our results, we attribute the superior PCA for KA7-BM due to the smaller crystallite size, the co-existence of mixed anatase-srilankite-rutile phases, and the consequent multiphase heterojunction formation, higher surface area, lattice disorder/strain generation, and surface oxygen environment. The present work demonstrates a feasible potential for the developed post-treatment strategy towards commercial prospects.

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Growth and characterization of gallium oxide films grown with nitrogen by plasma-assisted molecular-beam epitaxy

Cited by 23 publications

References 41 publications

Nano-engineering and functionalization of hybrid Au–Me_xO_y–TiO₂(Me = W, Ga) hetero-interfaces for optoelectronic receptors and nociceptors

Nano-engineering and functionalization of hybrid Au–Me_xO_y–TiO₂(Me = W, Ga) hetero-interfaces for optoelectronic receptors and nociceptors

Nanoscale All-Oxide-Heterostructured Bio-inspired Optoresponsive Nociceptor

Cost-Effective Production of TiO2 with 90-Fold Enhanced Photocatalytic Activity Via Facile Sequential Calcination and Ball Milling Post-Treatment Strategy

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Growth and characterization of gallium oxide films grown with nitrogen by plasma-assisted molecular-beam epitaxy

Cited by 23 publications

References 41 publications

Nano-engineering and functionalization of hybrid Au–MexOy–TiO2(Me = W, Ga) hetero-interfaces for optoelectronic receptors and nociceptors

Nano-engineering and functionalization of hybrid Au–MexOy–TiO2(Me = W, Ga) hetero-interfaces for optoelectronic receptors and nociceptors

Nanoscale All-Oxide-Heterostructured Bio-inspired Optoresponsive Nociceptor

Cost-Effective Production of TiO2 with 90-Fold Enhanced Photocatalytic Activity Via Facile Sequential Calcination and Ball Milling Post-Treatment Strategy

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Product

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Nano-engineering and functionalization of hybrid Au–Me_xO_y–TiO₂(Me = W, Ga) hetero-interfaces for optoelectronic receptors and nociceptors

Nano-engineering and functionalization of hybrid Au–Me_xO_y–TiO₂(Me = W, Ga) hetero-interfaces for optoelectronic receptors and nociceptors