scholarly journals Air Annealing Effect on Oxygen Vacancy Defects in Al-doped ZnO Films Grown by High-Speed Atmospheric Atomic Layer Deposition

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5043
Author(s):  
Chia-Hsun Hsu ◽  
Xin-Peng Geng ◽  
Wan-Yu Wu ◽  
Ming-Jie Zhao ◽  
Xiao-Ying Zhang ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
High Speed ◽  
Oxygen Vacancies ◽  
Annealing Temperature ◽  
Atomic Layer ◽  
Zno Films ◽  
X Ray ◽  
Layer Deposition

In this study, aluminum-doped zinc oxide (Al:ZnO) thin films were grown by high-speed atmospheric atomic layer deposition (AALD), and the effects of air annealing on film properties are investigated. The experimental results show that the thermal annealing can significantly reduce the amount of oxygen vacancies defects as evidenced by X-ray photoelectron spectroscopy spectra due to the in-diffusion of oxygen from air to the films. As shown by X-ray diffraction, the annealing repairs the crystalline structure and releases the stress. The absorption coefficient of the films increases with the annealing temperature due to the increased density. The annealing temperature reaching 600 °C leads to relatively significant changes in grain size and band gap. From the results of band gap and Hall-effect measurements, the annealing temperature lower than 600 °C reduces the oxygen vacancies defects acting as shallow donors, while it is suspected that the annealing temperature higher than 600 °C can further remove the oxygen defects introduced mid-gap states.

Oxygen Vacancies at the γ-Al2O3/STO Heterointerface Grown by Atomic Layer Deposition

2015 ◽  
Vol 1730 ◽  
Author(s):  
Thong Q. Ngo ◽  
Martin D. McDaniel ◽  
Agham Posadas ◽  
Alexander A. Demkov ◽  
John G. Ekerdt
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Atomic Layer ◽  
High Energy ◽  
Ex Situ ◽  
X Ray ◽  
Layer Deposition ◽  
Dimensional Electron Gas

ABSTRACTWe report the epitaxial growth of γ-Al2O3 on SrTiO3 (STO) substrates by atomic layer deposition (ALD). The ALD growth of γ-Al2O3 on STO(001) single crystal substrates was performed at a temperature of 345 °C. Trimethylaluminum and water were used as co-reactants. In-situ reflection high-energy electron diffraction and ex-situ x-ray diffraction were used to determine the crystallinity of the Al2O3 films. In-situ x-ray photoelectron spectroscopy was used to characterize the Al2O3/STO heterointerface. The formation of a Ti3+ feature is observed in the Ti 2p spectrum of STO after the first few ALD cycles of Al2O3 and even after exposure of the STO substrate to trimethylaluminum alone at 345 °C. The presence of a Ti3+ feature is a direct indication of oxygen vacancies at the Al2O3/STO heterointerface, which provide the carriers for the quasi-two dimensional electron gas at the interface.

scholarly journals Porous Silicon-Zinc Oxide Nanocomposites Prepared by Atomic Layer Deposition for Biophotonic Applications

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1987 ◽  
Author(s):  
Mykola Pavlenko ◽  
Valerii Myndrul ◽  
Gloria Gottardi ◽  
Emerson Coy ◽  
Mariusz Jancelewicz ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Porous Silicon ◽  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Atomic Layer ◽  
Visible Range ◽  
Optical Biosensing ◽  
X Ray ◽  
Layer Deposition

In the current research, a porous silicon/zinc oxide (PSi/ZnO) nanocomposite produced by a combination of metal-assisted chemical etching (MACE) and atomic layer deposition (ALD) methods is presented. The applicability of the composite for biophotonics (optical biosensing) was investigated. To characterize the structural and optical properties of the produced PSi/ZnO nanocomposites, several studies were performed: scanning and transmission electron microscopy (SEM/TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance, and photoluminescence (PL). It was found that the ALD ZnO layer fully covers the PSi, and it possesses a polycrystalline wurtzite structure. The effect of the number of ALD cycles and the type of Si doping on the optical properties of nanocomposites was determined. PL measurements showed a “shoulder-shape” emission in the visible range. The mechanisms of the observed PL were discussed. It was demonstrated that the improved PL performance of the PSi/ZnO nanocomposites could be used for implementation in optical biosensor applications. Furthermore, the produced PSi/ZnO nanocomposite was tested for optical/PL biosensing towards mycotoxins (Aflatoxin B1) detection, confirming the applicability of the nanocomposites.

scholarly journals Suppression of Oxygen Vacancy Defects in sALD-ZnO Films Annealed in Different Conditions

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3910
Author(s):  
Ming-Jie Zhao ◽  
Zhi-Tao Sun ◽  
Zhi-Xuan Zhang ◽  
Xin-Peng Geng ◽  
Wan-Yu Wu ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Carrier Concentration ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Atomic Layer ◽  
Zno Films ◽  
High Deposition Rate ◽  
Xps Spectra ◽  
Vacancy Defects ◽  
X Ray

Zinc oxide (ZnO) has drawn much attention due to its excellent optical and electrical properties. In this study, ZnO film was prepared by a high-deposition-rate spatial atomic layer deposition (ALD) and subjected to a post-annealing process to suppress the intrinsic defects and improve the crystallinity and film properties. The results show that the film thickness increases with annealing temperature owing to the increment of oxide layer caused by the suppression of oxygen vacancy defects as indicated by the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) spectra. The film transmittance is seldom influenced by annealing. The refractive index increases with annealing temperature at 300–700 °C, possibly due to higher density and crystallinity of the film. The band gap decreases after annealing, which should be ascribed to the decrease in carrier concentration according to Burstein–Moss model. The carrier concentration decreases with increasing annealing temperature at 300–700 °C since the oxygen vacancy defects are suppressed, then it increases at 800 °C possibly due to the out-diffusion of oxygen atoms from the film. Meanwhile, the carrier mobility increases with temperature due to higher crystallinity and larger crystallite size. The film resistivity increases at 300–700 °C then decreases at 800 °C, which should be ascribed primarily to the variation of carrier concentration.

Atomic Layer Deposition of TiN below 600 K Using N2H4

2018 ◽  
Vol 282 ◽  
pp. 232-237
Author(s):  
Adam Hinckley ◽  
Anthony Muscat
Keyword(s):  
Growth Rate ◽  
Atomic Layer Deposition ◽  
Titanium Nitride ◽  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
Detection Limits ◽  
Atomic Layer ◽  
Volatile Species ◽  
X Ray ◽  
Layer Deposition

Atomic layer deposition (ALD) was used to grow titanium nitride (TiN) on SiO2with TiCl4and N2H4. X-ray photoelectron spectroscopy (XPS) and ellipsometry were used to characterize film growth. A hydrogen-terminated Si (Si-H) surface was used as a reference to understand the reaction steps on SPM cleaned SiO2. The growth rate of TiN at 573 K doubled on Si-H compared to SiO2because of the formation of Si-N bonds. When the temperature was raised to 623 K, O transferred from Ti to Si to form Si-N when exposed to N2H4. Oxygen and Ti could be removed at 623 K by TiCl4producing volatile species. The added surface reactions reduce the Cl in the film below detection limits.

Electrical and Structural Properties of Ruthenium Film Grown by Atomic Layer Deposition Using Liquid-Phase Ru(CO)3(C6H8) Precursor

2007 ◽  
Vol 990 ◽  
Author(s):  
Sung-Hoon Chung ◽  
Vladislav Vasilyev ◽  
Evgeni Gorokhov ◽  
Yong-Won Song ◽  
Hyuk-Kyoo Jang
Keyword(s):  
Liquid Phase ◽  
Atomic Layer Deposition ◽  
Annealing Temperature ◽  
Atomic Layer ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Layer Deposition ◽  
Structural And Electrical Properties

ABSTRACTWe investigated effects of thermal annealing on Ru films deposited on the 8 inch Si substrates using a volatile liquid-phase Ru precursor, tricarbonyl-1,3-cyclohexadienyl ruthenium (Ru(CO)3(C6H8)) by an atomic layer deposition (ALD) technique. Structural and electrical properties of the films were characterized by scanning probe microscopy, X-ray diffractometry, sheet resistance. Grazing incidence X-ray diffraction (GIXRD) patterns show typical Ru hexagonal polycrystalline peaks as annealing temperature was increased. At the highest annealing temperature condition, Ta = 700 °C electrical resistivity become 6 times less than in as-deposited films.

scholarly journals Nickel Supported on Mesoporous Zirconium Oxide by Atomic Layer Deposition: Initial Fixed-Bed Reactor Study

2018 ◽  
Author(s):  
Riikka Puurunen ◽  
Pauline Voigt ◽  
Eero Haimi ◽  
Jouko Lahtinen ◽  
You Wayne Cheah ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Atomic Layer ◽  
Nickel Catalysts ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
X Ray ◽  
Fluorescence Measurements ◽  
Layer Deposition

Atomic layer deposition (ALD) is gaining attention as a catalyst preparation method able to produce metal (oxide, sulphide, etc.) nanoparticles of uniform size down to single atoms. This work reports our initial experiments to support nickel on mesoporous zirconia. Nickel (2,2,6,6-tetramethyl-3,5-heptanedionato)2 [Ni(thd)2] was reacted in a fixed-bed ALD reactor with zirconia, characterised with BET surface area of 72 m2/g and mean pore size of 14 nm. According to X-ray fluorescence measurements, the average nickel loading on the top part of the support bed was on the order of 1 wt-%, corresponding to circa one nickel atom per square nanometre. Cross-sectional scanning electron microscopy combined with energy-dispersive spectroscopy confirmed that in the top part of the fixed support bed, nickel was distributed throughout the zirconia particles. X-ray photoelectron spectroscopy indicated the nickel oxidation state to be two. Organic thd ligands remained complete on the surface after the Ni(thd)2 reaction with zirconia, as followed with diffuse reflectance infrared Fourier transform spectroscopy. The ligands could be fully removed by oxidation at 400 °C. These initial results indicate that nickel catalysts on zirconia can likely be made by ALD. Before catalytic testing, in addition to increasing the nickel loading by repeated ALD cycles, optimization of the process parameters is required to ensure uniform distribution of nickel throughout the support bed and within the zirconia particles.

scholarly journals Selective Growth of Al2O3 on Size-Selected Platinum Clusters by Atomic Layer Deposition

2019 ◽  
Author(s):  
Timothy J. Gorey ◽  
Yang Dai ◽  
Scott Anderson ◽  
Sungsik Lee ◽  
Sungwon Lee ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Atomic Layer ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Dimensional Structure ◽  
Alumina Layer ◽  
X Ray ◽  
Layer Deposition

In heterogeneous catalysis, atomic layer deposition (ALD) has been developed as a tool to stabilize and reduce carbon deposition on supported nanoparticles. Here, we discuss use of high vacuum ALD to deposit alumina films on size-selected, sub-nanometer Pt/SiO2 model catalysts. Mass-selected Pt24 clusters were deposited on oxidized Si(100), to form model Pt24/SiO2 catalysts with particles shown to be just under 1 nm, with multilayer three dimensional structure. Alternating exposures to trimethylaluminum and water vapor in an ultra-high vacuum chamber were used to grow alumina on the samples without exposing them to air. The samples were probed in situ using X-ray photoelectron spectroscopy (XPS), low-energy ion scattering spectroscopy (ISS), and CO temperature-programmed desorption (TPD). Additional samples were prepared for ex situ experiments using grazing incidence small angle x-ray scattering spectroscopy (GISAXS). Alumina growth is found to initiate at least 60 times more efficiently at the Pt24 cluster sites, compared to bare SiO2/Si, with a single ALD cycle depositing a full alumina layer on top of the clusters, with substantial additional alumina growth initiating on SiO2 sites surrounding the clusters. As a result, the clusters were completely passivated, with no exposed Pt binding sites.

scholarly journals Ambient pressure x-ray photoelectron spectroscopy setup for synchrotron-based in situ and operando atomic layer deposition research

2022 ◽  
Vol 93 (1) ◽  
pp. 013905
Author(s):  
E. Kokkonen ◽  
M. Kaipio ◽  
H.-E. Nieminen ◽  
F. Rehman ◽  
V. Miikkulainen ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
Atomic Layer ◽  
X Ray ◽  
Layer Deposition
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