Refine
Year of publication
Document Type
Keywords
- atomic layer deposition (13)
- atomic layer deposition (ALD) (9)
- HfO2 (7)
- TiO2 (7)
- water splitting (7)
- Al2O3 (6)
- Atomic layer deposition (ALD) (6)
- InP (4)
- dielectric (4)
- ALD (3)
- Synchrotron Radiation Photoelectron Spectroscopy (3)
- Wet chemical treatment (3)
- X-ray absorption spectroscopy (XAS) (3)
- XPS (3)
- resonant photoelectron spectroscopy (3)
- GaAs (2)
- III/V (2)
- PE-ALD (2)
- Scanning tunneling microscopy (STM) (2)
- Si(111) (2)
- Synchrotron Photoemission Spectroscopy (2)
- X-Ray photoelectron spectroscopy (2)
- X-ray absorption spectroscopy (2)
- X-ray photoelectron spectroscopy (2)
- X-ray photoelectron spectroscopy (XPS) (2)
- charge neutrality level (CNL) (2)
- chemical vapor deposition (2)
- dielectric properties (2)
- ellipsometry (2)
- in situ (2)
- iron oxide (2)
- passivation (2)
- photoelectron spectroscopy (2)
- photoemission (2)
- titanium dioxide (TiO2) (2)
- transmission electron microscopy (TEM) (2)
- ultrathin (2)
- water oxidation (2)
- Al-Mg alloy (1)
- Al:HfO2 (1)
- Aluminum oxide (Al₂O₃) (1)
- Al₂O₃ (1)
- Amorphous (1)
- Anatase (1)
- Atomic Layer deposition (1)
- Atomic force microscopy (1)
- Atomic layer deposition (1)
- Atomlagenabscheidung (1)
- Atomlagenabscheidung (ALD) (1)
- Auger processes (1)
- Band scheme (1)
- Charging (1)
- Cyclic voltammetry (CV) (1)
- Dichroism (1)
- EXAFS (1)
- Erbium (1)
- Frenkel defects (1)
- GIXRD (1)
- Ga2O3 (1)
- Gd:HfO2 (1)
- Graphene Oxide (1)
- HOPG (1)
- Hafnium oxide (1)
- Hafnium oxide (HfO₂) (1)
- Hematite (1)
- HfO2 thin films (1)
- III−V (1)
- Interfaces (1)
- Intrinsic charges (1)
- Intrinsic defects (1)
- Korrosion (1)
- Linear Scan Voltametry (1)
- Medium Energy Ion Scattering Spectroscopy (MEIS) (1)
- Nanocrystals (1)
- Nanowires (1)
- Oxid-Doped (1)
- Partial density of states (pDOS) (1)
- Passivierung (1)
- Photoelectrode (1)
- Photoelektronenspektroskopie (1)
- Photokathoden (1)
- Plasma enhanced atomic layer deposition (1)
- Raman spectroscopy (1)
- Resonant photoelectron spectroscopy (resPES) (1)
- RuOx (1)
- Ruthenium (1)
- Rutherford backscattering (RBS) (1)
- Scanning Tunneling Microscopy (1)
- Si photocathodes (1)
- Si photoelectrode (1)
- Si photoelectrodes (1)
- Si, TiO2 , Al2O3 and RuO2 substrates (1)
- Si2p (1)
- Silicon carbide (1)
- Silicon dioxide (1)
- Silizium (1)
- Structure (1)
- Synchrotron-radiation photoelectron spectroscopy (SRPES) (1)
- TMA (1)
- Titanium oxide(TiO₂) (1)
- X-Ray absorption spectroscopy (1)
- X-Ray absorption spectroscopy (XAS) (1)
- X-ray diffraction (XRD) (1)
- X-ray linear dichroism (1)
- XAS (1)
- Zirconium (1)
- ald (1)
- angle-resolved (1)
- atomic Layer deposition (1)
- atomic layer depsoition (ALD) (1)
- band gab (1)
- capacitance-voltage (1)
- capacitance-voltage (CV) (1)
- catalyst (1)
- charge neutrality level (1)
- charge transfer multiplet (1)
- cobalt iron oxides (1)
- cobalt oxide catalyst (1)
- control of crytallinity (1)
- covalency (1)
- current-voltage (IV) (1)
- defect states (1)
- density functional theory (1)
- doping dependence (1)
- efficiency enhancement (1)
- electro-catalysis (1)
- electrochemical (1)
- electronic structure (1)
- energy conversion (1)
- engineering (1)
- equivalent oxide thickness (EOT) (1)
- field emission scanning electron microscopy (FESEM) (1)
- fixed oxide charge (1)
- gadolinium aluminate (1)
- gate stack (1)
- hafnia thin films (1)
- height distribution (1)
- hematite (1)
- heterostructures (1)
- high-k (1)
- high-k dielectrics (1)
- in-gap states (1)
- in-situ2 (1)
- interface engineering (1)
- interface state density (1)
- interfaces (1)
- iron magnesium oxide (1)
- leakage current (1)
- magnetization (1)
- materials (1)
- microscope (1)
- microstructure (1)
- microsystems (1)
- morphology (1)
- moöecuar beam epxitaxy (MBE) (1)
- nano-functional (1)
- near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) (1)
- negative fixe Oxidladungen (1)
- offset (1)
- organic (1)
- oxidic (1)
- oxygen plasma treatment (1)
- oxygen reduction reaction (1)
- partial density of states (pDOS) (1)
- passivation layer (1)
- permittivity (1)
- perovskite (1)
- photoactivated properties (1)
- photoanode (1)
- photocatalysis (1)
- photochemical (1)
- photocorrosion (1)
- photoelectrochemical device (PEC device) (1)
- photoelectron (1)
- photoemission spectroscopy (1)
- photon-induced degradation (1)
- plasma enhanced atomic layer deposition (1)
- protection layer (1)
- quantum size effects (1)
- random (1)
- rare earth oxide (1)
- resonant photoemission spectroscopy (resPES) (1)
- rutile (1)
- scalability (1)
- scanning electron microscopy (SEM) (1)
- scanning tunneling micrsocopy (1)
- seed layer (1)
- self assembled monolayers (SAM) (1)
- silicon (Si) (1)
- spectroscopic ellipsometry (1)
- stepped surfaces (1)
- sulfur passivation (1)
- synchrotron (1)
- synchrotron radiation (1)
- synchrotron radiation photoelectron spectroscopy (SR-PES) (1)
- thickness dependence (1)
- time of flight secondary ion mass spectrometry (TOFSIMS) (1)
- titanium oxide (TiO2) (1)
- titanomagnetite (1)
- titanum oxide (TiO2) (1)
- water oxidation reaction (1)
- x-ray absorption spectroscopy (1)
Institute
BTU
The TiO2 films are prepared by atomic layer deposition (ALD) method using titanium
isopropoxide precursors at 250 °C and analyzed using resonant photoemission spectroscopy (resPES). We report on the Ti2p and O1s core levels, on the valence band (VB) spectra and
x-ray absorption spectroscopy (XAS) data, and on the resonant photoelectron spectroscopy (resPES) profiles at the O1s and the Ti3p absorption edges. We determine the elemental
abundance, the position of the VB maxima, the partial density of states (PDOS) in the VB and in the conduction band (CB) and collect these data in a band scheme. In addition, we analyze the band-gap states as well as the intrinsic states due to polarons and charge-transfer
excitations. These states are found to cause multiple Auger decay processes upon resonant
excitation. We identify several of these processes and determine their relative contribution to the Auger signal quantitatively. As our resPES data allow a quantitative analysis of these defect states, we determine the relative abundance of the PDOS in the VB and in CB and also the charge neutrality level.
The anatase and rutile polymorphs of TiO2 are analyzed in the same way as the TiO2 ALD layer. The electronic properties of the TiO2ALD layer are compared with the anatase and rutile polymorphs of TiO2. In our comparative study, we find that ALD has its own
characteristic electronic structure that is distinct from that of anatase and rutile. However, many details of the electronic structure are comparable and we benefit from our spectroscopic
data and our careful analysis to find these differences. These can be attributed to a stronger hybridization of the O2p and Ti3d4s states for the ALD films when compared to the anatase and rutile polymorphs.
For several years, scientists have been trying to understand the mechanisms that reduce the long‐term stability of perovskite solar cells. In this work, we examined the effect of water and photon flux on the stability of CH3NH3PbI3 perovskite films and solar cells using in situ near‐ambient pressure X‐ray photoelectron spectroscopy (NAP‐XPS), field emission scanning electron microscopy (FESEM), and current density–voltage (J–V) characterization. The used amount of water vapor (up to 1 mbar) had a negligible impact on the perovskite film. The higher the photon flux, the more prominent were the changes in the NAP‐XPS and FESEM data; also, a faster decline in power conversion efficiency (PCE) and a more substantial hysteresis in the J‐V characteristics were observed. Based on our results, it can be concluded that the PCE decrease originates from the creation of Frenkel pair defects in the perovskite film under illumination. The stronger the illumination, the higher the number of Frenkel defects, leading to a faster PCE decline and more substantial hysteresis in the J‐V sweeps.
The passivation of n-type InP (100) using sulfur in combination with a gadolinium aluminate (GAO) dielectric layer has been studied. Photoluminescence, minority-carrier lifetime, and capacitance−voltage measurements indicate that a (NH4)2S vapor passivation step prior to atomic layer deposition of the oxide effectively lowers the interface state density. Surface and interface chemistry were studied by synchrotron radiation photoemission spectroscopy (SRPES). The effect of ex situ surface passivation after native oxide removal in HCl solution was examined. It was observed that surface reoxidation occurred during (NH4)2S vapor exposure, leading to the formation of Inx(HPO4)y. S was present on the surface as a sulfide in both surface and subsurface sites. After atomic layer deposition of GAO, sulfates were detected in addition to Inx(HPO4)y, which was confirmed by near-edge X-ray absorptionfine structure analysis. The S in the stack was quantified using reference-free grazing incidence X-rayfluorescence
analysis. X-ray absorption spectroscopy showed that Gd was oxidized and present in the 3+ oxidation state, most likely as a phosphate close to the InP interface and possibly mixed with sulfates. Energy-dependent SRPES measurements of Al 2p and Gd 4d core levels, complemented by transmission electron microscopy, further suggest that the dielectric layer was segregated. Valence band measurements confirm the effective passivation of InP, indicating unpinning of the surface Fermi level.
Oxide surface coatings are of importance in tailoring interface properties with respect to surface passivation, adjustment of surface potentials, or providing active centers for surface reactions. In this contribution, we report about surface coatings prepared by the atomic layer deposition (ALD) method. ALD is known for its conformal growth of ultrathin, dense films which exhibit a low concentration of pinholes.
Ultra-small rock salt cobalt monoxide (CoO) nanoparticles were synthesized and subjected to partial oxidation (‘corrosion’) with ceric ammonium nitrate (CAN) to form mixed-valence CoOx(1 < x< 2) water oxidation catalysts. Spectroscopic, microscopic and analytical methods evidenced a structural reformation of cubic CoO to active CoOx with a spinel structure. The superior water oxidation activity of CoOx has been established in electrochemical water oxidation under alkaline conditions.
Electrochemical water oxidation with CoOx was recorded at a considerably low overpotential of merely 325 mV at a current density of 10 mA cm-2 in comparison to 370 mV for CoO. Transformation of both octahedral CoII and CoIII sites into amorphous Co(OH)2–CoOOH is the key to high electrochemical activity while the presence of a higher amount of octahedral CoIII sites in CoOx is imperative for an efficient oxygen evolution process.