Незаполненные электронные состояния ультратонких пленок тиофен-фенилен со-олигомеров на поверхности поликристаллического золота

The results of a study of the unoccupied electronic states of ultrathin films of bis-carboxyphenyl-phthalide (DCA-DPP) and bis-methylphenyl-phthalide (DM-DPP) up to 8 nm thick are presented. The studies were carried out by total current spectroscopy (TCS) technique in the energy range from 5 eV to 20 eV above EF during thermal vacuum deposition of these organic films on the surface of highly oriented pyrolytic graphite (HOPG). The energy Evac relative to EF, that is, the electronic work function of the DM-DPP films, at a film thickness of 5–8 nm was 4.3 ± 0.1 eV. The electronic work function of the DCA-DPP films was 3.7 ± 0.1 eV. The structure of the maxima of the unoccupied electronic states of DCA-DPP films and DM-DPP films in the studied energy range is determined. The properties determined of DCA-DPP and DM-DPP films are compared with the properties of films of unsubstituted diphenylphthalide (DPP). According to our analysis, –CH3 substitution of the DPP molecule practically did not affect the height of the potential barrier between the film and the HOPG surface, and –COOH substitution of the DPP molecule led to an increase in the height of the potential barrier between the film and the HOPG substrate surface by 0.5–0.6 eV. Substitution of DPP molecules with –COOH functional groups which represents formation of DCA-DPP molecules led to a shift of two peaks of the experimental total current spectra located at energies in the range from 5 eV to 8 eV above EF, by about 1 eV towards lower electron energies.

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Незаполненные электронные состояния ультратонких пленок кватерфенила на поверхностях послойно сформированного CdS и окисленного кремния

Физика твердого тела ◽

10.21883/ftt.2021.08.51175.071 ◽

2021 ◽

Vol 63 (8) ◽

pp. 1177

Author(s):

А.С. Комолов ◽

Э.Ф. Лазнева ◽

Н.Б. Герасимова ◽

В.С. Соболев ◽

Е.В. Жижин ◽

...

Keyword(s):

Work Function ◽

Ultrathin Films ◽

Photoelectron Spectroscopy ◽

Atomic Layer ◽

Physicochemical Interaction ◽

Total Current ◽

Thermal Vacuum ◽

Layer Deposition ◽

Cds Film ◽

A Minor

The results of a study of unoccupied electronic states and the formation of a boundary potential barrier during thermal vacuum deposition of ultrathin films of 4-quaterphenyl oligophenylene on the surface of CdS and on the surface of oxidized silicon are presented. Using X-ray photoelectron spectroscopy (XPS) it was determined, that the atomic concentrations of Cd and S were equal in the surface layer of a 75-nm-thick CdS film formed by atomic layer deposition (ALD). The electronic properties of 4-quaterphenyl films up to 8 nm thick were studied during their deposition on the surface of the CdS layer and on the surface of oxidized silicon using total current spectroscopy (TCS) in the energy range from 5 eV to 20 eV above EF. The energetic position of the main maxima of the fine structure of the total current spectra (FSTCS) of 4-quaterphenyl films was determined. The location of the maxima was reproducible when two selected substrate materials were used. A minor decrease in the work function, from 4.2 eV to 4.1 eV, was registered during the thermal deposition of 4-quaterphenyl onto the CdS surface. During the deposition of a 4-quaterphenyl film on the oxidized silicon surface, an increase in the work function from 4.2 eV to 4.5 eV was found. Possible mechanisms of the physicochemical interaction between the 4-quaterphenyl film and the surface of the investigated substrates, which lead to a difference in the observed values of the work function of the films on these substrates, are discussed.

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Atomic Layer Deposition of LiF and Lithium Ion Conducting (AlF3)(LiF)x Alloys Using Trimethylaluminum, Lithium Hexamethyldisilazide and Hydrogen Fluoride

10.26434/chemrxiv.5459653 ◽

2017 ◽

Author(s):

Younghee Lee ◽

Daniela M. Piper ◽

Andrew S. Cavanagh ◽

Matthias J. Young ◽

Se-Hee Lee ◽

...

Keyword(s):

Lithium Ion ◽

Atomic Layer ◽

Mass Gain ◽

Alloy Film ◽

Ex Situ ◽

X Ray ◽

Layer Deposition ◽

Ion Conducting ◽

Good Agreement

<div>Atomic layer deposition (ALD) of LiF and lithium ion conducting (AlF3)(LiF)x alloys was developed using trimethylaluminum, lithium hexamethyldisilazide (LiHMDS) and hydrogen fluoride derived from HF-pyridine solution. ALD of LiF was studied using in situ quartz crystal microbalance (QCM) and in situ quadrupole mass spectrometer (QMS) at reaction temperatures between 125°C and 250°C. A mass gain per cycle of 12 ng/(cm2 cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH3)3 as a reaction byproduct instead of HMDS at 150°C. LiF ALD showed self-limiting behavior. Ex situ measurements using X-ray reflectivity (XRR) and spectroscopic ellipsometry (SE) showed a growth rate of 0.5-0.6 Å/cycle, in good agreement with the in situ QCM measurements.</div><div>ALD of lithium ion conducting (AlF3)(LiF)x alloys was also demonstrated using in situ QCM and in situ QMS at reaction temperatures at 150°C A mass gain per sequence of 22 ng/(cm2 cycle) was obtained from QCM measurements at 150°C. Ex situ measurements using XRR and SE showed a linear growth rate of 0.9 Å/sequence, in good agreement with the in situ QCM measurements. Stoichiometry between AlF3 and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF3)(LiF)x alloy consists of aluminum, lithium and fluorine. Carbon, oxygen, and nitrogen impurities were both below the detection limit of XPS. Grazing incidence X-ray diffraction (GIXRD) observed that LiF and (AlF3)(LiF)x alloy film have crystalline structures. Inductively coupled plasma mass spectrometry (ICP-MS) and ionic chromatography revealed atomic ratio of Li:F=1:1.1 and Al:Li:F=1:2.7: 5.4 for (AlF3)(LiF)x alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF3)(LiF)x alloy film was measured as σ = 7.5 × 10-6 S/cm.</div>

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Applications of Synchrotron Surface X-Ray Scattering Studies of Electrochemical Interfaces

MRS Bulletin ◽

10.1557/s088376940005171x ◽

1999 ◽

Vol 24 (1) ◽

pp. 36-40 ◽

Cited By ~ 6

Author(s):

Hoydoo You ◽

Zoltán Nagy

Keyword(s):

Surface Science ◽

Region Of Interest ◽

Atomic Layer ◽

Living Environment ◽

Ex Situ ◽

Spectroscopic Techniques ◽

Engineering Research ◽

Significant Intensity ◽

Electrochemical Interfaces

Aqueous-solution/solid interfaces are ubiquitous in modern manufacturing environments as well as in our living environment, and studies of such interfaces are an active area of science and engineering research. An important area is the study of liquid/solid interfaces under active electrochemical control, which has many immediate technological implications, for example, corrosion/passivation of metals and energy storage in batteries and ultracapacitors. The central phenomenon of electrochemistry is the charge transfer at the interface, and the region of interest is usually wider than a single atomic layer, ranging from a monolayer to thousands of angstroms, extending into both phases.Despite the technological and environmental importance of liquid/solid interfaces, the atomic level understanding of such interfaces had been very much hampered by the absence of nondestructive, in situ experimental techniques. The situation has changed somewhat in recent decades with the development of the largely ex situ ultrahigh vacuum (UHV) surface science, modern spectroscopic techniques, and modern surface microscopy.However in situ experiments of electrochemical interfaces are difficult, stemming from the special nature of these interfaces. These are so-called buried interfaces in which the solid electrode surface is covered by a relatively thick liquid layer. For this reason, the probe we use in the structural investigation must satisfy simultaneously two conditions: (1) the technique must be surface/interface sensitive, and (2) absorption of the probe in the liquid phase must be sufficiently small for penetration to and from the interface of interest without significant intensity loss.

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Electron Work Function–An Effective Parameter for In-situ Reflection of Electron Activities in Various Processes

Journal of Biosensors & Bioelectronics ◽

10.4172/2155-6210.1000e123 ◽

2013 ◽

Vol 04 (04) ◽

Author(s):

Dongyang Li

Keyword(s):

Work Function ◽

Electron Work Function ◽

Effective Parameter

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Resistive switching of in situ and ex situ oxygen plasma treated ZnO thin film deposited by atomic layer deposition

Applied Physics A ◽

10.1007/s00339-014-8324-4 ◽

2014 ◽

Vol 116 (2) ◽

pp. 663-669 ◽

Cited By ~ 10

Author(s):

Jian Zhang ◽

Hui Yang ◽

Qilong Zhang ◽

Hao Jiang ◽

Jikui Luo ◽

...

Keyword(s):

Thin Film ◽

Atomic Layer Deposition ◽

Resistive Switching ◽

Oxygen Plasma ◽

Atomic Layer ◽

Ex Situ ◽

Zno Thin Film ◽

Layer Deposition

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Незаполненные электронные состояния ультратонких пленок дифенилфталида на поверхности высокоупорядоченного пиролитического графита

Физика твердого тела ◽

10.21883/ftt.2019.10.48277.497 ◽

2019 ◽

Vol 61 (10) ◽

pp. 1960

Author(s):

А.С. Комолов ◽

Э.Ф. Лазнева ◽

Н.Б. Герасимова ◽

В.С. Соболев ◽

С.А. Пшеничнюк ◽

...

Keyword(s):

Negative Charge ◽

Pyrolytic Graphite ◽

Electron Work Function ◽

Electronic States ◽

Low Energy ◽

Atomic Composition ◽

Total Current ◽

Organic Film ◽

X Ray ◽

Calculation Results

AbstractThe results of diagnostics of the atomic composition of a diphenylphthalide (DPP) film thermally precipitated in vacuum by the of X-ray photoelectric spectroscopy (XPS) method are presented. The results of examination of the unoccupied electronic states of the ultrathin DPP films with the thickness up to 10 nm on the surface of the highly oriented pyrolytic graphite (HOPG) by the total current spectroscopy (TCS) method in the energy range from 5 to 20 eV above E _F are presented. In this range, the main maxima in the total current spectra are identified. The analysis of the TCS results with consideration of the theoretical calculation results has shown that the low-energy maxima observed at the energies from 6 to 7.5 eV are induced predominately by π* electron orbitals of DPP films. The values of the energy E _vac in relation to E _F, i.e., of the electron work function in the DPP films at the film thickness of 5–10 nm, are found experimentally at a level of 4.3 ± 0.1 eV. The negative charge transfer from an organic film to the substrate corresponds to the formation of the HOPG/DPP boundary potential barrier during the thermal deposition of the DPP film.

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Atomic Layer Deposition of LiF and Lithium Ion Conducting (AlF3)(LiF)x Alloys Using Trimethylaluminum, Lithium Hexamethyldisilazide and Hydrogen Fluoride

10.26434/chemrxiv.5459653.v1 ◽

2017 ◽

Cited By ~ 1

Author(s):

Younghee Lee ◽

Daniela M. Piper ◽

Andrew S. Cavanagh ◽

Matthias J. Young ◽

Se-Hee Lee ◽

...

Keyword(s):

Lithium Ion ◽

Atomic Layer ◽

Mass Gain ◽

Alloy Film ◽

Ex Situ ◽

X Ray ◽

Layer Deposition ◽

Ion Conducting ◽

Good Agreement

<div>Atomic layer deposition (ALD) of LiF and lithium ion conducting (AlF3)(LiF)x alloys was developed using trimethylaluminum, lithium hexamethyldisilazide (LiHMDS) and hydrogen fluoride derived from HF-pyridine solution. ALD of LiF was studied using in situ quartz crystal microbalance (QCM) and in situ quadrupole mass spectrometer (QMS) at reaction temperatures between 125°C and 250°C. A mass gain per cycle of 12 ng/(cm2 cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH3)3 as a reaction byproduct instead of HMDS at 150°C. LiF ALD showed self-limiting behavior. Ex situ measurements using X-ray reflectivity (XRR) and spectroscopic ellipsometry (SE) showed a growth rate of 0.5-0.6 Å/cycle, in good agreement with the in situ QCM measurements.</div><div>ALD of lithium ion conducting (AlF3)(LiF)x alloys was also demonstrated using in situ QCM and in situ QMS at reaction temperatures at 150°C A mass gain per sequence of 22 ng/(cm2 cycle) was obtained from QCM measurements at 150°C. Ex situ measurements using XRR and SE showed a linear growth rate of 0.9 Å/sequence, in good agreement with the in situ QCM measurements. Stoichiometry between AlF3 and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF3)(LiF)x alloy consists of aluminum, lithium and fluorine. Carbon, oxygen, and nitrogen impurities were both below the detection limit of XPS. Grazing incidence X-ray diffraction (GIXRD) observed that LiF and (AlF3)(LiF)x alloy film have crystalline structures. Inductively coupled plasma mass spectrometry (ICP-MS) and ionic chromatography revealed atomic ratio of Li:F=1:1.1 and Al:Li:F=1:2.7: 5.4 for (AlF3)(LiF)x alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF3)(LiF)x alloy film was measured as σ = 7.5 × 10-6 S/cm.</div>

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Atomic Layer Deposition of ZnO on Mesoporous Silica: Insights into Growth Behavior of ZnO via In-Situ Thermogravimetric Analysis

Nanomaterials ◽

10.3390/nano10050981 ◽

2020 ◽

Vol 10 (5) ◽

pp. 981 ◽

Cited By ~ 2

Author(s):

Piyush Ingale ◽

Kristian Knemeyer ◽

Mar Piernavieja Hermida ◽

Raoul Naumann d’Alnoncourt ◽

Arne Thomas ◽

...

Keyword(s):

Thermogravimetric Analysis ◽

Atomic Layer Deposition ◽

Reaction Mechanisms ◽

High Surface ◽

High Surface Area ◽

Atomic Layer ◽

Ex Situ ◽

Direct Access ◽

Layer Deposition

ZnO is a remarkable material with many applications in electronics and catalysis. Atomic layer deposition (ALD) of ZnO on flat substrates is an industrially applied and well-known process. Various studies describe the growth of ZnO layers on flat substrates. However, the growth characteristics and reaction mechanisms of atomic layer deposition of ZnO on mesoporous powders have not been well studied. This study investigates the ZnO ALD process based on diethylzinc (DEZn) and water with silica powder as substrate. In-situ thermogravimetric analysis gives direct access to the growth rates and reaction mechanisms of this process. Ex-situ analytics, e.g., N2 sorption analysis, XRD, XRF, HRTEM, and STEM-EDX mapping, confirm deposition of homogenous and thin films of ZnO on SiO2. In summary, this study offers new insights into the fundamentals of an ALD process on high surface area powders.

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