Extracting band edge profiles at semiconductor heterostructures from hard-x-ray core-level photoelectron spectra

Sushko, Peter V.; Chambers, Scott A.

doi:10.1038/s41598-020-69658-9

Cited by 16 publications

(6 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the core-level XPS spectra consist of a large number of spectra with slightly different binding energies that manifest in a broadening of the recorded spectra. 52,53 Remarkably, the apparent peak broadening is most pronounced for the Sr 3d region under oxidizing conditions, which results in a significantly flattened intensity valley in between the Sr 3d (Sr 3d 5/2 and Sr 3d 3/2 ) doublet. This observation may indicate the evolution of a minor SrO or Sr(OH) 2 surface phase, which is contributing to the signal in form of a second, superimposed doublet of slightly different binding energy.…”

mentioning

confidence: 99%

Space charge governs the kinetics of metal exsolution

Weber

Breuer

Rose

et al. 2023

Preprint

View full text Add to dashboard Cite

Nanostructured composite electrode materials play a major role in the field of catalysis and electrochemistry. Self‐assembly of metallic nanoparticles on oxide supports via metal exsolution relies on the transport of reducible dopants towards the perovskite surface to provide accessible catalytic centers at the solid/gas interface. However, it is unclear if exsolution can be driven from the oxide bulk or if the process is limited to surfaces and interfaces, where strong electrostatic gradients and space charges typically control the properties of oxides. Here we reveal that the nature of the surface‐dopant interaction is the main determining factor for the exsolution kinetics of nickel in SrTi0.9Nb0.05Ni0.05O3‐ẟ and that the exsolution depth is strongly limited to the near‐surface region of the perovskite oxide. Electrostatic interaction of dopants with surface space charge regions forming upon thermal annealing result in strong surface passivation i.e. a retarded exsolution response. We furthermore demonstrate the controllability of the exsolution response via engineering of the perovskite surface chemistry. Our findings indicate that tailoring the electrostatic gradients at the perovskite surface is an essential step to improve exsolution type materials in catalytic converters.

show abstract

mentioning

confidence: 99%

Space charge governs the kinetics of metal exsolution

Weber

Breuer

Rose

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…The anomaly arises from the crystal of Si or STO that is minimally affected by surface core-level shifts and band bending, and is assigned to the different layers in the heterojunction. As described in detail elsewhere [2,23],…”

Section: Resultsmentioning

confidence: 99%

Tuning band alignment at a semiconductor-crystalline oxide heterojunction via electrostatic modulation of the interfacial dipole

Chrysler

Gabel

Lee

et al. 2021

Phys. Rev. Materials

View full text Add to dashboard Cite

We demonstrate that the interfacial dipole associated with bonding across the SrTiO3/Si heterojunction can be tuned through space charge, thereby enabling the band alignment to be altered via doping. Oxygen impurities in Si act as donors that create space charge by transferring electrons across the interface into SrTiO3. The space charge induces an electric field that modifies the interfacial dipole, thereby tuning the band alignment from type-II to type-III. The transferred charge, resulting in built-in electric fields, and change in band alignment are manifested in electrical transport and hard x-ray photoelectron spectroscopy measurements. Ab initio models reveal the interplay between polarization and band offsets. We find that band offsets can be tuned by modulating the density of space charge across the interface.Functionalizing the interface dipole to enable electrostatic altering of band alignment opens new pathways to realize novel behavior in semiconducting heterojunctions.

show abstract

“…The angle-dependent hard x-ray photoemission spectroscopy (with hv = 3 keV) has been performed at Berlin Electron Storage Ring Society for Synchrotron Radiation to analyze the depth-profiled interface electron gas of LaAlO 3 /SrTiO 3 heterostructures, and the results supported an electronic reconstruction in the LaAlO 3 overlayer as the driving force for the 2D electron gas (2DEG) formation 35 . Using hard XPS, the impact of oxygen on the band structure at the Ni/GaN interface was revealed 36 , the band edge profiles at the semiconductor heterostructures were extracted 37 , and the core-level shifts at the buried GaP/Si(001) interfaces were reported 38 . Aforementioned typical studied cases already demonstrated the powerful capability of hard XPS for buried interface analysis.…”

Section: Determination Of Interface Electronic States Using Photoemission Spectroscopymentioning

confidence: 99%

Determination of the embedded electronic states at nanoscale interface via surface-sensitive photoemission spectroscopy

Wang

Lin

et al. 2021

Light Sci Appl

View full text Add to dashboard Cite

The fabrication of small-scale electronics usually involves the integration of different functional materials. The electronic states at the nanoscale interface plays an important role in the device performance and the exotic interface physics. Photoemission spectroscopy is a powerful technique to probe electronic structures of valence band. However, this is a surface-sensitive technique that is usually considered not suitable for the probing of buried interface states, due to the limitation of electron-mean-free path. This article reviews several approaches that have been used to extend the surface-sensitive techniques to investigate the buried interface states, which include hard X-ray photoemission spectroscopy, resonant soft X-ray angle-resolved photoemission spectroscopy and thickness-dependent photoemission spectroscopy. Especially, a quantitative modeling method is introduced to extract the buried interface states based on the film thickness-dependent photoemission spectra obtained from an integrated experimental system equipped with in-situ growth and photoemission techniques. This quantitative modeling method shall be helpful to further understand the interfacial electronic states between functional materials and determine the interface layers.

show abstract

Extracting band edge profiles at semiconductor heterostructures from hard-x-ray core-level photoelectron spectra

Cited by 16 publications

References 36 publications

Space charge governs the kinetics of metal exsolution

Space charge governs the kinetics of metal exsolution

Tuning band alignment at a semiconductor-crystalline oxide heterojunction via electrostatic modulation of the interfacial dipole

Determination of the embedded electronic states at nanoscale interface via surface-sensitive photoemission spectroscopy

Contact Info

Product

Resources

About