Polyamide films were grown on Si(111) using a molecular layer deposition (MLD) process with 1,2-ethylenediamine and trimesoyl chloride precursors at 120 °C. Synthesized polyamide films on Si(111) were then pyrolyzed in vacuum (10−7 Torr) to yield crystalline SiC thin films. High-resolution transmission electron microscope images of heat-treated samples showed the heteroepitaxial nature of the synthesized 3C-SiC (β-SiC) with respect to the Si(111) substrate. Raman, x-ray photoelectron spectroscopy, and x-ray diffraction analysis confirmed the formation of single-crystal SiC films. Samples pyrolyzed at 1300 °C showed defects attributed to Si sublimation. Formation of highly conformal SiC film after pyrolysis was demonstrated using Bosch-processed Si trenches. The thicknesses of 3C-SiC films obtained after pyrolysis were linearly dependent on the number of MLD cycles used to deposit polyamide films.
Molecular layer deposition (MLD) of thin polyamide films was performed using 1,3,5-benzenetricarbonyltrichloride (trimesoyl chloride, TMC) and 1,2-ethylenediamine (EDA) as precursors at a temperature of 120°С. The growth rate at this temperature was 1.85 nm/cycle. In situ quartz crystal microbalance (QCM) study was used to determine the film growth behavior. QCM signal showed linear film growth with an increasing number of MLD cycles. Pyrolysis of MLD polyamide films on Si(111) was conducted at temperatures of 1100 and 1300°С and a pressure of 10 −7 Torr. Thin heteroepitaxial films of β-SiC (3C–SiC) on the Si(111) were obtained as a result of a solid-phase reaction between Si and C at 1300°С. A variety of high-resolution spectroscopic techniques were used to determine the elemental composition and crystal structure of organic and ceramic films.
Objective: determination of the antibacterial properties of modified TiO2 films on the colonies of Staphylococcus aureus and Escherichia coli bacteria. Comparison of antibacterial properties of samples of TiO2 films doped with different elements. Materials and methods. Synthesis and modification of TiO2 films were carried out by atomic / molecular-layer deposition in a hot-wall reactor. The antibacterial properties of the films were determined by comparing the concentrations of bacterial cultures of S. aureus and E. coli irradiated with UV and natural light in the presence of TiO2 films with the control. Results. The lowest concentration of bacterial cultures after the incubation period was in the case of the TiON and TiAlN samples, which indicates that they are the most effective. The samples of TiN and V2O5: TiO2 films showed relatively high activity. In the case of undoped TiO2, the lowest activity was observed compared to other samples, which confirms the absence of antibacterial properties for TiO2 in the visible spectra. Cunclusion. The tested samples of TiO2-based thin films (doped with N, C and vanadium), obtained by Atomic and Molecular Layer Deposition Techniques, have high antibacterial activity against bacterial cultures of sanitary indicative microorganisms Staphylococcus aureus and Escherichia coli.
Цель: определение антибактериальных свойств модифицированных пленок TiO2 на колониях бактерий Staphylococcus aureus и Escherichia coli. Сравнение антибактериальных свойств образцов пленок TiO2 легированных разными элементами. Материалы и методы. Синтез и модификация пленок TiO2 осуществлены методами атомно/молекулярнослоевого осаждения в ректоре с горячими стенками (hotwall reactor). Антибактериальные свойства пленок определены путем сравнения концентрации бактериальных культур S. aureus и E. coli облученных УФ и естественным светом в присутствии пленок TiO2 с контролем. Результаты. Наименьшее количество бактериальных культур после инкубациионного периода было в случае образцов TiON и TiAlN, что свидутульствует об их наибольшей антибактериальной. Относительно высокую активность проявили образцы пленок TiN и V2O5:TiO2. В случае недопированного TiO2 наблюдалась наименьшая активность по сравнению с другими образцами, что подтверждает отсутствие антибактериальных свойств для TiO2 в видимой области солнечного света. Заключение. Испытанные образцы тонких пленок на основе TiO22 (легированные N, C и ванадием), полученных методами АСО и МСО, обладают высокой антибактериальной активностью по отношению к бактериальным культурам санитарнопоказательных микроорганизмов S. aureus и E. coli.
In this work, atomic-layer deposition (ALD) of yttrium oxide (Y 2 O 3 ) was demonstrated using tris(butylcyclopentadienyl)yttrium (Y(CpBut) 3 ) and H 2 O . Yttrium precursor showed thermal stability and a high reactivity in surface reactions with H 2 O. In situ monitoring of the deposition process by quartz crystal microbalance (QCM) showed that the growth of oxide is accompanied by the absorption of water into the bulk of the film, which can lead to chemical vapor deposition (CVD) type processes. Reducing amount of dosed water as well as purge time extension during ALD cycling allow to mitigate the CVD effects. The Y 2 O 3 film growth rate 230°C varied depending on the number of cycles and had maximum value of 1.7 Å/cycle. The films obtained at 230°C had a cubic polycrystalline structure with an average density of 96% of the Y 2 O 3 bulk density. The X-ray photoelectron spectroscopy (XPS) measurements showed a carbon impurity level below the detections limit (~0.2 at %). The O/Y atomic concentration ratio estimated by Rutherford backscattering spectroscopy (RBS) was ~1.58. As deposited Y 2 O 3 films had a refractive index of 1.85 (at 632.8 nm), whereas with protective ALD Al 2 O 3 film, the refractive index was 1.73.
This work presents the results of the study of the antibacterial properties of samples of TiO2, TiON, TiN, TiAlN, TiO2:V2O5 ultrathin films synthesized by Atomic and Molecular Layer Deposition (ALD/MLD) techniques. The studies were conducted on the colonies of the E. coli and S.aureus bacteria. It was found that samples of TiON films exhibit the greatest antibacterial activity. After an hour of exposure of the TiON samples under UV light with 365 nm wave length in presence of colonies of E. coli bacteria, the activity was 93.32%, and under normal daylight it was 74.60%, which is higher than for undoped TiO2 samples with activity of 53.80% in UV light and 21.1% in daylight. Similar results were obtained with colonies of S.aureus bacteria, where the efficiency values were slightly lower due to the higher viability of these bacteria.
In this work Molecular layer deposition (MLD) technique used to synthesize titanium-vanadium (TiV x C y O z ) and aluminum-vanadium (AlV x C y O z ) hybrid organic-inorganic films via alternating surface reactions of titanium tetrachloride (or trimethylaluminum), vanadium oxochloride, and ethylene glycol. Using in situ monitoring it was found that the surface reactions were self-limiting at temperatures of 90 and 115°C. The coating thickness per molecular layer deposition cycle (growth rate) at 115°C on a silicon substrate varied from 5.8 to 11.4 Å/cycle, and the film densities, from 1.7 to 2.0 g cm –3 . An analysis of the samples obtained at 115°C revealed their amorphous structure. A thermal treatment of titanium-vanadium films at 450°C in air resulted in formation of highly structured coatings. These coatings were composed of nanowires of single-crystal vanadium oxide (V 2 O 5 ) and mixed nanostructures of titanium and vanadium oxides. Increase in thermal treatment temperature to 500°C resulted in elongation of the V 2 O 5 nanowires up to tens of micrometers and in their separation from the substrate. A thermal treatment of aluminum-vanadium films in air resulted in formation of a low-density film. Pyrolysis of the films in an inert gas yielded composite coatings containing domains of graphitized carbon. These films can be potentially useful in modern devices for energy storage, electronics, medicine and other promising fields of technology.
Thin films of aluminum nitride and oxynitride were deposited by atomic layer deposition (ALD) in the temperature range from 170 to 290°C (optimal deposition temperature 200–230°C). Tris(dimethylamido) aluminum and ammonia were used as precursors for the atomic layer deposition of aluminum nitride (AlN). The average AlN film thickness per ALD cycle (deposition rate) at 200°C was ~0.8 Å. Films were deposited on a silicon <100> substracte with a native oxide layer. The N/Al atomic concentration ratio in the obtained films was ~1.3. Aluminum oxynitride films obtained by periodical dose of water vapor in the course of atomic layer deposition of AlN at 200°C. The composition of the deposited oxynitride films was Al0.5O0.43N0.07.