Valence and Conduction Band Offsets for InN and III-Nitride Ternary Alloys on (−201) Bulk β-Ga<sub>2</sub>O<sub>3</sub>

Fares, Chaker; Tadjer, Marko J.; Woodward, J.; Nepal, Neeraj; Mastro, Michael A.; Eddy, Charles Jr R.; Ren, F.; Pearton, S. J.

doi:10.1149/2.0281907jss

Cited by 18 publications

(7 citation statements)

References 48 publications

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“…Additionally, the maximum energy of the valence band (VBM) was determined to be 2.29 eV by the XPS analysis of the CsPbBr 3 QD-MoS 2 nanoflakes. , From these results, the electronic structure (band edge position) of the CsPbBr 3 QD-MoS 2 nanoflakes was determined.…”

Section: Resultsmentioning

confidence: 99%

Cesium Lead Bromide (CsPbBr₃) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays

Kim

Bong

Park

et al. 2021

ACS Appl. Mater. Interfaces

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Chemiluminescence immunoassays have been widely employed for diagnosing various diseases. However, because of the extremely low intensity chemiluminescence signals, highly sensitive transducers, such as photomultiplier tubes and image sensors with cooling devices, are required to overcome this drawback. In this study, a hypersensitive photosensor was developed based on cesium lead bromide (CsPbBr 3 ) perovskite quantum dots (QDs) with sufficient high sensitivity for chemiluminescence immunoassays. First, CsPbBr 3 QDs with a highly uniform size, that is, 5 nm, were synthesized under thermodynamic control to achieve a high size confinement effect. For the fabrication of the photosensor, MoS 2 nanoflakes were used as an electron transfer layer and heat-treated at an optimum temperature. Additionally, a parylene-C film was used as a passivation layer to improve the physical stability and sensitivity of the photosensor. In particular, the trap states on the CsPbBr 3 QDs were reduced by the passivation layer, and the sensitivity was increased. Finally, a photosensor based on CsPbBr 3 QDs was employed in chemiluminescence immunoassays for the detection of human hepatitis B surface antigen, human immunodeficiency virus antibody, and alpha-fetoprotein (AFP, a cancer biomarker). When compared with the conventionally used equipment, the photosensor was determined to be feasible for application in chemiluminescence immunoassays.

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Section: Resultsmentioning

confidence: 99%

Cesium Lead Bromide (CsPbBr₃) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays

Kim

Bong

Park

et al. 2021

ACS Appl. Mater. Interfaces

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“…XPS valence band spectra of the nanomaterials are used to predict the valence band maximum of each material following the reported method. [ 71 ] The rising edge of the peak present in the XPS valence band spectra is extrapolated to the baseline of the flat XPS valence band spectra as shown in Figure , and the intercept of the baseline is reported as the maximum of the valence band ( E v ). Fermi energy level ( E f ) is assumed to be at zero eV, hence E v is reported in negative energy values in Table 4.…”

Section: Resultsmentioning

confidence: 99%

Unraveling the Effect of the Chemical and Structural Composition of Zn_xNi_1−xFe₂O₄ on the Electron Transfer at the Electrochemical Interface

Madagalam,

Bartoli,

Rosito

et al. 2023

Small Structures

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In order to deepen the understanding of the role of transition metal oxides in electron transfer at the electrochemical interface, the performance of Zn x Ni1−x Fe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) nanomaterials in electrochemical sensing is studied. Nanomaterials are synthesized by simple autocombustion synthesis procedure. Field‐emission scanning electron microscopy characterization shows that the particles have a size between 30 and 70 nm with an average crystallite size between 24 and 35 nm. The bandgap energies of the nanomaterials, as estimated by UV–vis experiments, are in the 2.32–2.56 eV range. The valence band maximum is evaluated using X‐ray photoelectron spectroscopy and the position of the conduction band minimum is estimated. The ZnFe2O4 sensor has the best performances: highest rate constant (13.1 ± 2.8 ms−1), lowest peak‐to‐peak separation (386 ± 2 mV), and highest sensitivity (37.75 ± 0.17 μA mM−1). Its limit of detection (7.94 ± 0.04 μM) is second best, and its sensitivity is more than twice the sensitivity of the bare sensor (16.7 ± 0.9 μA mM−1). Nanomaterials energy bands mapping with the experimental redox potentials is performed to predict the electron transfer at the electrochemical interface, and the importance of surface states/defects is highlighted in the electron transfer mechanism.

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“…Analysis of XPS valence band (VB) spectra is more challenging than core line analysis due to the complex nature of valence orbital contributions and interactions. Typical XPS analysis of the VB region band can reveal chemical changes induced by doping, − defect and carrier behavior in semiconductors, − or measure band offsets at a heterojunction. − The work function of surfaces may also be measured by analysis of XPS valence bands, although this is more commonly carried out with ultraviolet photoemission spectroscopy (UPS).…”

Section: Introductionmentioning

confidence: 99%

Phase Quantification of Heterogeneous Surfaces Using DFT-Simulated Valence Band Photoemission Spectra

Lee

Quesada-Cabrera

Willis

et al. 2023

ACS Appl. Mater. Interfaces

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Quantifying the crystallographic phases present at a surface is an important challenge in fields such as functional materials and surface science. X-ray photoelectron spectroscopy (XPS) is routinely employed in surface characterization to identify and quantify chemical species through core line analysis. Valence band (VB) spectra contain characteristic but complex features that provide information on the electronic density of states (DoS) and thus can be understood theoretically using density functional theory (DFT). Here, we present a method of fitting experimental photoemission spectra with DFT models for quantitative analysis of heterogeneous systems, specifically mapping the anatase to rutile ratio across the surface of mixed-phase TiO 2 thin films. The results were correlated with mapped photocatalytic activity measured using a resazurin-based smart ink. This method allows large-scale functional and surface composition mapping in heterogeneous systems and demonstrates the unique insights gained from DFT-simulated spectra on the electronic structure origins of complex VB spectral features.

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Valence and Conduction Band Offsets for InN and III-Nitride Ternary Alloys on (−201) Bulk β-Ga₂O₃

Cited by 18 publications

References 48 publications

Cesium Lead Bromide (CsPbBr₃) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays

Cesium Lead Bromide (CsPbBr₃) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays

Unraveling the Effect of the Chemical and Structural Composition of Zn_xNi_1−xFe₂O₄ on the Electron Transfer at the Electrochemical Interface

Phase Quantification of Heterogeneous Surfaces Using DFT-Simulated Valence Band Photoemission Spectra

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Valence and Conduction Band Offsets for InN and III-Nitride Ternary Alloys on (−201) Bulk β-Ga2O3

Cited by 18 publications

References 48 publications

Cesium Lead Bromide (CsPbBr3) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays

Cesium Lead Bromide (CsPbBr3) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays

Unraveling the Effect of the Chemical and Structural Composition of ZnxNi1−xFe2O4 on the Electron Transfer at the Electrochemical Interface

Phase Quantification of Heterogeneous Surfaces Using DFT-Simulated Valence Band Photoemission Spectra

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Product

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Valence and Conduction Band Offsets for InN and III-Nitride Ternary Alloys on (−201) Bulk β-Ga₂O₃

Cesium Lead Bromide (CsPbBr₃) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays

Cesium Lead Bromide (CsPbBr₃) Perovskite Quantum Dot-Based Photosensor for Chemiluminescence Immunoassays

Unraveling the Effect of the Chemical and Structural Composition of Zn_xNi_1−xFe₂O₄ on the Electron Transfer at the Electrochemical Interface