Valence band offset of β-Ga2O3/wurtzite GaN heterostructure measured by X-ray photoelectron spectroscopy

Wei, Wei; Qin, Zhixin; Fan, Shunfei; Li, Zhiwei; Shi, Kai; Zhu, Qinsheng; Zhang, Guoyi

doi:10.1186/1556-276x-7-562

Cited by 114 publications

(63 citation statements)

References 19 publications

(17 reference statements)

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“…Note that the lower Ga surface versus bulk content for the m-Ga 2 O 3 reference reflects oxygen termination of gallium surfaces [57]. O 1s XP spectra of HZSM-5 revealed a single broad peak with a 533 eV binding energy associated with Si-O-Si and Si-O-Al environments [58,59] (Figure 3a), which was unaffected by low levels of Ga doping, but shifted to lower binding energy for 10Ga/HZSM-5, approaching that of Ga 2 O 3 at 530.7 eV [60,61]. A similar trend was observed for the Ga 2p 3/2 XP spectra (Figure 3b), which exhibited a single broad peak at 1119.0 eV for low Ga loadings, whose binding energy decreased towards that of m-Ga 2 O 3 at 1117.9 eV for 10Ga/HZSM-5 [62].…”

Section: Crystallitementioning

confidence: 99%

Ga/HZSM-5 Catalysed Acetic Acid Ketonisation for Upgrading of Biomass Pyrolysis Vapours

et al. 2019

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Pyrolysis bio-oils contain significant amounts of carboxylic acids which limit their utility as biofuels. Ketonisation of carboxylic acids within biomass pyrolysis vapours is a potential route to upgrade the energy content and stability of the resulting bio-oil condensate, but requires active, selective and coke-resistant solid acid catalysts. Here we explore the vapour phase ketonisation of acetic acid over Ga-doped HZSM-5. Weak Lewis acid sites were identified as the active species responsible for acetic acid ketonisation to acetone at 350 °C and 400 °C. Turnover frequencies were proportional to Ga loading, reaching ~6 min−1 at 400 °C for 10Ga/HZSM-5. Selectivity to the desired acetone product correlated with the weak:strong acid site ratio, being favoured over weak Lewis acid sites and reaching 30% for 10Ga/HZSM-5. Strong Brønsted acidity promoted competing unselective reactions and carbon laydown. 10Ga/HZSM-5 exhibited good stability for over 5 h on-stream acetic acid ketonisation.

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Section: Crystallitementioning

confidence: 99%

Ga/HZSM-5 Catalysed Acetic Acid Ketonisation for Upgrading of Biomass Pyrolysis Vapours

et al. 2019

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“…The frequent occurrence of the (−201) peak on the surface of the oxidised GaN is another reason that stimulates the study of the interface between this facet and water ,. GaN‐based sensor technologies have been investigated extensively to detect gas, pH, biochemicals and various ions in solution .…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory Simulations of Water Adsorption and Activation on the (−201) β‐Ga₂O₃ Surface

Anvari

Spagnoli

Parish

et al. 2018

Chemistry A European J

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Density functional theory calculations are used to study the molecular and dissociative adsorption of water on the (-201) β-Ga O surface. The effect of adsorption of different water-like species on the geometry, binding energies, vibrational spectra and the electronic structure of the surface are discussed. The study shows that although the hydrogen evolution reaction requires a small amount of energy to become energetically favourable, the over potential for activating the oxygen evolution reaction is quite high. The results of our calculations provide insight as to why a high voltage is required in experiments to activate the water-splitting reaction, whereas previous studies of gallium oxide predicted very low activation energies for other energetically more favourable facets. Application of this work to studies of GaN-based chemical sensors with gallium oxide surfaces shows that it is possible to select the gate bias so that the sensors are not influenced by water-splitting reactions. It was also found that in the region where water splitting does not occur, the surface can exist in two states, that is, water or hydroxyl terminated.

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“…(d), the high‐resolution XPS of O 1s can be also fitted with three chemical states at binding energies of 530.7 eV, 532.2 eV and 533.8 eV. The deconvoluted peaks close to 531 eV and around 532 eV represent Ga―O bond and Al―O bond, respectively, which indicates that O contamination mainly exists in the form of oxide. In Fig.…”

Section: Resultsmentioning

confidence: 99%

XPS study of impurities in Si‐doped AlN film

Liang

Chen

Zhao

et al. 2016

Surface & Interface Analysis

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This paper reports an XPS study of impurities in a 100‐nm‐thick AlN film grown by metalorganic chemical vapor deposition (MOCVD) under low pressure on the n‐type 6H‐SiC substrate. The Si‐doped AlN film was characterized by the X‐ray photoelectron spectroscopy (XPS) in a high vacuum system, which reveals the content distribution and chemical states of impurities along depth. The XPS analysis of AlN film before and after argon‐ion etching indicates that there always exist Ga, O and C contaminations in AlN film. Especially, O contamination on the AlN film surface is mostly introduced during the growth of AlN layer by MOCVD. Meanwhile, most of O atoms bind with Al or Ga in Al―O and Ga―O chemical states. In particular, the Ga atoms in AlN film are always in two chemical states, i.e. Ga―Ga bond and Ga―O bond, which demonstrates that the aggregation of Ga is accompanying with AlN growth. Copyright © 2016 John Wiley & Sons, Ltd.

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Valence band offset of β-Ga2O3/wurtzite GaN heterostructure measured by X-ray photoelectron spectroscopy

Cited by 114 publications

References 19 publications

Ga/HZSM-5 Catalysed Acetic Acid Ketonisation for Upgrading of Biomass Pyrolysis Vapours

Ga/HZSM-5 Catalysed Acetic Acid Ketonisation for Upgrading of Biomass Pyrolysis Vapours

Density Functional Theory Simulations of Water Adsorption and Activation on the (−201) β‐Ga₂O₃ Surface

XPS study of impurities in Si‐doped AlN film

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Valence band offset of β-Ga2O3/wurtzite GaN heterostructure measured by X-ray photoelectron spectroscopy

Cited by 114 publications

References 19 publications

Ga/HZSM-5 Catalysed Acetic Acid Ketonisation for Upgrading of Biomass Pyrolysis Vapours

Ga/HZSM-5 Catalysed Acetic Acid Ketonisation for Upgrading of Biomass Pyrolysis Vapours

Density Functional Theory Simulations of Water Adsorption and Activation on the (−201) β‐Ga2O3 Surface

XPS study of impurities in Si‐doped AlN film

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Density Functional Theory Simulations of Water Adsorption and Activation on the (−201) β‐Ga₂O₃ Surface