Band alignment and electronic structure of the anatase TiO2/SrTiO3(001) heterostructure integrated on Si(001)

Abstract

Using density functional theory (DFT), scanning transmission electron microscopy (STEM), and electron energy loss spectroscopy (EELS) we study the interface structure and electronic properties of the anataseTiO 2 /SrTiO 3 (001) heterostructure epitaxially grown on Si (001) by molecular beam epitaxy (MBE). We show that charge transfer at the TiO 2 /SrTiO 3 interface is induced by the chemical bond formation between Ti and O. Subsequent O lattice polarization is found to be the leading screening mechanism at the interface. By comparing the theoretical local electronic structure to the O K edge EELS spectra taken at the interface with atomic resolution, we are able to trace how the local band structure evolves in response to the change in symmetry and bonding across the interface. We also discuss the effect of interfacial point defects (O vacancy and F impurity) on the band alignment.

Selective isolation of the electron or hole in photocatalysis: ZnO–TiO2 and TiO2–ZnO core–shell structured heterojunction nanofibers via electrospinning and atomic layer deposition

“…We have not considered the possible emission from the interface, as the oxide hetero-interfaces are not completely understood yet. 17 Nevertheless, the present design enables future studies to identify the role of each charge-carrier for oxidation processes of various organic compounds, see ref. 50 and 72-81 in ref.…”

“…17 Further complicating the process of charge transfer, the oxide hetero-interfaces are not well understood yet. 17 In the present case initial precursor nanobers of ZnO or TiO 2 were produced, then the counter semiconductor is deposited.…”

“…17 Further complicating the process of charge transfer, the oxide hetero-interfaces are not well understood yet. 17 In the present case initial precursor nanobers of ZnO or TiO 2 were produced, then the counter semiconductor is deposited. This intermediate level heterostructure was subjected to calcination, producing the hetero-oxide interface with a structural distortion along with a probability of chemical bonds and charge distribution across the junction.…”

“…However, it is notable that the charge exchange process and hence the mechanism of PCA at heterojunction is still unclear even aer the decades of research. 17 Nevertheless, if one of the charge carriers can be effectively isolated from the catalysis then this would offer useful insights for future studies on the design of new catalytic materials. In this direction, we have exploited the fundamental behavior of photo-generated charge carriers in semiconductor heterojunctions, and fabricated 'core-shell' nanobers where only one of the semiconductors participates in the PCA, while the counter semiconductor allows the diffusion of either an electron or hole depending on the band alignment.…”

Achieving Type I, II, and III Heterojunctions Using Functionalized MXene

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Indeed, various heterostructures have been experimentally developed by metal-semiconductor contact or the junction of two other semiconductors. 15 They have shown attractive electronic and optical characteristics in a number of diverse fields.…”