Article
Chemistry, Physical
Brijmohan Paramanik, Debajyoti Das
Summary: In this study, diamond-like carbon (DLC) films with well distinguished nanocrystalline diamond (NCD) grains embedded in the matrix were grown on glass substrates without any pre-treatment using a specially-designed stainless-steel shadow-mask assembly. The composition of the precursor gas and gas pressure in the plasma significantly influenced the relative composition of different carbon phases in the films. The optimum NCD embedded DLC film exhibited a homogeneous microstructure with uniform distribution of NCD grains and high optical transmittance.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Xin Chen, Markus Mohr, Kai Bruehne, Hans-Joerg Fecht
Summary: The high electrical conductivity of over 100 S/cm was achieved in nanocrystalline diamond films deposited on silicon single-crystalline substrates by using a methane and hydrogen process gas mixture in an appropriate hot-filament CVD process without further dopant. Oxygen reactive-ion etching process was found to improve the diamond film surface's electron affinity, leading to a reduction in specific contact resistance. The mechanism behind the contact resistance reduction was explained qualitatively in terms of the electron affinity of the diamond surface, confirmed through XPS, AFM, and surface wetting measurements.
Review
Chemistry, Multidisciplinary
Soumen Mandal
Summary: Diamond thin films, similar to bulk diamond, have applications in various fields. Techniques for diamond nucleation and seeding, such as electrostatic seeding and bias enhanced nucleation, are discussed for different substrates. Each technique has its own advantages and disadvantages depending on the substrate material and requirements.
Article
Materials Science, Multidisciplinary
Yabo Huang, Liangxian Chen, Siwu Shao, Xiaohua Zhu, Ke Huang, Kang An, Yuting Zheng, Jinlong Liu, Junjun Wei, Chengming Li
Summary: In this study, Er2O3 antireflective films were deposited on CVD diamond substrates using RF magnetron sputtering, and the effects of deposition temperature on the structure, chemical composition, and properties of the films were investigated. Results showed that with increasing deposition temperature, the deposition rate, grain size, and surface roughness of the films increased. Furthermore, hardness and modulus of the Er2O3 antireflective films were enhanced at higher deposition temperatures, improving IR transmittance and adhesion strength on the CVD diamond substrates.
Article
Chemistry, Physical
William G. S. Leigh, Jerome A. Cuenca, Evan L. H. Thomas, Soumen Mandal, Oliver A. Williams
Summary: This study demonstrates an in-situ method of mapping substrate temperature under MPECVD growth conditions, and compares the temperature maps with simulated plasma electron densities. The results show an increase in temperature and simulated plasma density towards the center of the substrate holder. Properties of nanocrystalline diamond films, measured using ex-situ Raman spectroscopy and spectroscopic ellipsometry, also demonstrate the impact of substrate temperature inhomogeneity during growth.
Article
Thermodynamics
Luke Yates, Zhe Cheng, Tingyu Bai, Karl Hobart, Marko Tadjer, Tatyana Feygelson, Bradford B. Pate, Mark Goorsky, Samuel Graham
Summary: As wide bandgap electronic devices continue to advance, effective thermal management becomes crucial. Growing chemical vapor deposited (CVD) diamond directly onto the transistor substrate has been shown to provide an effective solution. However, measuring both thermal conductivity and heat capacity simultaneously is difficult due to the complex microstructure near the interface between CVD diamond and electronic material.
NANOSCALE AND MICROSCALE THERMOPHYSICAL ENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
Yoshinori Saiki, Takahiro Bando, Toru Harigai, Hirofumi Takikawa, Takahiro Hattori, Hiroaki Sugita, Natsue Kawahara, Kunihiko Tanaka
Summary: Through the investigation of the mechanism of nonuniform film formation on cemented tungsten carbide with a Co binder substrates, it was found that the Co particles on the substrate surface and the uplift of WC grains caused by carbon filament generation led to the nonuniform formation of diamond films. Therefore, preventing the segregation of Co in the initial stage is crucial to achieve a good-quality uniform film.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Chemistry, Physical
Elena B. Yudina, Alexander E. Aleksenskii, Sergey A. Bogdanov, Sergey S. Bukalov, Larisa A. Leites, Dmitry B. Radishev, Anatoly L. Vikharev, Alexander Y. Vul'
Summary: This paper presents experimental results on the formation of Eu ions' luminescent centers in CVD diamond films. A new approach using diamond nanoparticles surface modified with Eu ions for seeding during CVD growth has been implemented. The growth of Eu-doped nanocrystalline diamond films (NCD) on silicon substrates through microwave plasma-assisted CVD at 2.45 GHz resulted in distinct photoluminescence spectra, confirming the incorporation of Eu ions into the NCD film.
Article
Materials Science, Multidisciplinary
Makoto Kasu, Ryota Takaya, Seong-Woo Kim
Summary: This study investigates the residual strain and curvature of diamond in relation to different substrates. The results show that diamond has lower tensile strain and can grow a 2-inch layer without cracking on the Ir/sapphire substrate. The convex curvature of diamond on sapphire is larger compared to that on MgO substrate.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Azadeh Valinattaj Omran, Chaimaa Mahi, Romain Vayron, Celine Falentin-Daudre, Fabien Benedic
Summary: This study investigated the characteristics of nanocrystalline diamond films synthesized at low surface temperature on Ti-6Al-4V substrates for biomedical applications. The surface roughness of the substrates was varied by different polishing grits. Regardless of the polishing protocol, nanocrystalline diamond coatings with comparable morphology and purity to those on silicon substrates were achieved. However, the polishing protocol significantly affected the roughness and hardness of the films, with the finest polishing grit leading to increased hardness values.
Review
Materials Science, Multidisciplinary
Chunyan Zhang, Ratnakar D. D. Vispute, Kun Fu, Chaoying Ni
Summary: This review focuses on the thermal properties of chemical vapor deposited diamond thin films and their importance in thermal management and other applications. Diamond offers unique opportunities in thermal management due to its exceptional properties, such as high thermal conductivity and radiation hardness.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Yue Takamori, Masatsugu Nagai, Taira Tabakoya, Yuto Nakamura, Satoshi Yamasaki, Christoph E. Nebel, Xufang Zhang, Tsubasa Matsumoto, Takao Inokuma, Norio Tokuda
Summary: In order to improve the growth rate of diamond films, single-crystalline (100) diamond films were grown using hot-filament chemical vapor deposition (HFCVD), with investigations into the methane/hydrogen concentration (CH4/H-2) and filament-temperature dependence on growth rate. The growth process was found to be governed by reactions on the filament surface, particularly the decomposition of CH4 and the formation of CH3, with an estimated activation energy of 440 kJ/mol.
DIAMOND AND RELATED MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Hiroyuki Nishinaka, Kazuki Shimazoe, Kazutaka Kanegae, Masahiro Yoshimoto
Summary: The study conducted mist chemical vapor deposition to fabricate alpha-Ga2O3 epitaxial thin films on alpha-Fe2O3 substrates. XRD analysis confirmed the epitaxial growth of c-plane alpha-Ga2O3 thin films on c-plane alpha-Fe2O3 substrates. The use of alpha-Fe2O3 substrates resulted in lower asymmetric diffraction (10-14) full width at half maximum for alpha-Ga2O3 compared to alpha-Al2O3. Additionally, XRD pole figure analysis indicated that alpha-Ga2O3 on alpha-Fe2O3 had no in-plane rotations, suggesting that alpha-Fe2O3 substrates with small lattice mismatches are promising for alpha-Ga2O3 without rotational domains.
Article
Materials Science, Multidisciplinary
Chaimaa Mahi, Ovidiu Brinza, Riadh Issaoui, Jocelyn Achard, Fabien Benedic
Summary: This study investigates the potential of synthesizing nanocrystalline diamond (NCD) films on glass substrates using a Distributed Antenna Array (DAA) microwave system operating at low temperature and low pressure. The results show that the best film properties are achieved at a substrate temperature below 300 degrees C, including high transmittance, low absorption coefficient, and low surface roughness. The wettability of the surface also changes from hydrophilic to hydrophobic after NCD deposition.
Article
Chemistry, Physical
Victor Ralchenko, Vadim Sedov, Artem Martyanov, Valery Voronov, Sergey Savin, Andrey Khomich, Mikhail Shevchenko, Andrey Bolshakov
Summary: We report on the growth of novel microcrystalline diamond-germanium composite films on Si substrates using microwave plasma assisted chemical vapor deposition. The structure of the films strongly depends on the deposition temperature, with competing Ge grains and diamond crystallites at lower temperatures, and enhanced diamond growth at higher temperatures. The composite shows optical transmission for wavelengths above 10 mm and exhibits bright optical emission of GeV color centers at 601 nm. The effective coefficient of thermal expansion can be tuned by adjusting the Ge volume fraction, facilitating integration with semiconductor wafers.
Article
Materials Science, Multidisciplinary
O. Romanyuk, J. Zemek, J. Houdkova, O. Babcenko, E. Shagieva, K. Beranova, A. Kromka, P. Jiricek
Summary: A hydrogenated nanocrystalline diamond (NCD-H) film was prepared using chemical vapor deposition (CVD) method, and the surface destruction and graphitization of NCD-H were achieved through Ar ion bombardment by monoatomic beam (Ar+) and cluster ion beam (ArCIB). ArCIB bombardment resulted in the formation of a thin altered layer on the surface of NCD-H, while Ar+ beam bombardment created a thicker, homogeneous altered layer. Multiple microscopy and spectroscopy methods were used to evaluate the contribution of C-Hx bonds to the asymmetry of the C 1s core level line shape and measure the H concentration on the surface. The study demonstrates the limitations of Auger spectroscopy (D-parameter) analysis for measuring the sp2/sp3 phase concentration on rough NCD-H surfaces. The controllable amorphization or graphitization of diamond surface can enhance its functionality in detectors, electrochemical sensing, or supercapacitor applications.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Athanasios Koliogiorgos, Tomas Polcar, Bohuslav Rezek
Summary: The interaction between protoporphyrin molecules and Si nanocrystals is studied using different methods. The results show electron charge transfer and energy transfer effects depending on the orientation and distance between the molecules. A distance-dependent fluorescence resonance energy transfer (FRET) is observed, and smaller Si nanocrystals have larger couplings. The addition of plasmon nanoparticles as a bridge enhances the coupling, and using Au nanoparticles shows increased energy transfer rates and lower distance dependence.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Egor Ukraintsev, Hadi Hematian, Bohuslav Rezek
Summary: This study investigates the effect of surface polarity of zinc oxide (ZnO) on the adsorption of thiorphan, a small molecule with important biological roles. The results show that polar ZnO surfaces form thiorphan nanodots, while nonpolar ZnO surfaces self-assemble into layered nanoislands. The findings provide insights for controlling the assembly of thiorphan and other molecular nanomaterials for diverse applications.
Article
Chemistry, Multidisciplinary
Frantisek Trojanek, Karol Hamracek, Martin Hanak, Marian Varga, Alexander Kromka, Oleg Babcenko, Lukas Ondic, Petr Maly
Summary: Diamond thin films with a high-density of light-emitting negatively charged silicon vacancy (SiV) centers can be prepared at a relatively low cost, which has potential applications in photonics or sensing. The composition of the films, which consist of diamond grains with SiV centers and sp(2)-carbon phase, can be adjusted by changing the preparation conditions. Surface defects and the sp(2)-related defects in the grains can trap the carriers excited within the SiV centers, leading to a decrease in their internal photoluminescence (PL) quantum efficiency.
Article
Chemistry, Multidisciplinary
Vaclav Houska, Egor Ukraintsev, Jaroslav Vacek, Jiri Rybacek, Lucie Bednarova, Radek Pohl, Irena G. Stara, Bohuslav Rezek, Ivo Stary
Summary: The synthesis of helically chiral macrocycles composed of dibenzo[5]helicene units and trans-stilbene-4,4'-diyl linkers is reported. Different stereoisomers of these macrocycles were obtained through chiral resolution. The self-assembly of these macrocycles into long 1D molecular stripes in ordered 2D nanocrystals was studied using AFM.
Article
Instruments & Instrumentation
Jakub Budil, Pavla Stenclova, Alexander Kromka, Petra Liskova
Summary: In this study, infrared attenuated total reflection spectroscopy coupled with optical and confocal laser scanning microscopy was used to analyze the real-time development of Pseudomonas syringae biofilm. The kinetics of representative band areas in the spectral window 4000-800 cm(-1) were analyzed to characterize different developmental stages of the biofilm.
APPLIED SPECTROSCOPY
(2023)
Article
Materials Science, Multidisciplinary
Katerina Kolarova, Irena Bydzovska, Oleksandr Romanyuk, Ekaterina Shagieva, Egor Ukraintsev, Alexander Kromka, Bohuslav Rezek, Stepan Stehlik
Summary: Hydrogenation of the surface provides specific and unique properties to nanodiamonds. In this study, high-pressure high-temperature nanodiamonds (HPHT NDs) with varying levels of hydrogenation and sp2 carbon content were prepared and characterized. Higher surface sp2-C content and hydrogenation levels led to better dispersibility in acidic to neutral pH and higher isoelectric points. Chitosan was found to electrostatically attract hydrogenated HPHT NDs, improving their dispersibility and providing colloidal stability in a wide pH range of 2-11. Chitosan coating enables the decoration of hydrogenated HPHT NDs with silver nanoparticles.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Oksana Gutsul, Ondrej Szabo, Nirmal Kumar, Rene Pfeifer, Branislav Dzurnak, Kezia Sasitharan, Vsevolod Slobodyan, Alexander Kromka, Bohuslav Rezek
Summary: MXenes have unique properties that make them promising materials for sustainable energy technologies, including high electrical conductivity, hydrophilicity, excellent thermal stability, large interlayer spacing, easily tunable structure, high surface area, and microporous structure that facilitate faster ion transfer. This study compares the electrical properties of MXene thin films prepared from aqueous and non-aqueous solvents. The results show that MXene deposited from the non-aqueous solvent DMF exhibits higher electrical conductivity than that deposited from NMP. This suggests that MXene thin films prepared from non-aqueous solvents may have potential applications as charge-transporting layers in hybrid photovoltaic devices.
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Energy & Fuels
Aurelien Sokeng Djoumessi, Anastasia Sichwardt, Daria Miliaieva, Jan Cermak, Maximilian Schaal, Felix Otto, Stepan Stehlik, Jaroslav Kulicek, Vojtech Nadazdy, Torsten Fritz, Alexander Kromka, Bohuslav Rezek, Ulrich S. S. Schubert, Harald Hoppe
Summary: Diamond nanoparticles, also known as nanodiamonds, have attracted scientific interest due to their optical and electronic properties, nontoxicity, biocompatibility, and large surface area. The versatility of the surface chemistry of nanodiamonds allows for the attachment of various functional groups, providing a platform for adjusting their properties and functions. In this study, high-pressure high-temperature nanodiamonds were tested as charge extraction material in organic solar cells, and hydrogenated nanodiamonds were found to be effective for electron extraction.
Article
Nanoscience & Nanotechnology
Michal Koci, Tibor Izsak, Gabriel Vanko, Michaela Sojkova, Jana Hrda, Ondrej Szabo, Miroslav Husak, Karol Vegso, Marian Varga, Alexander Kromka
Summary: This study synthesizes MoS2 and H-NCD thin films using appropriate physical/chemical deposition methods, and analyzes their performance in gas sensing properties. The results show that the MoS2/H-NCD heterostructure-based gas sensor exhibits improved sensitivity to oxidizing NO2 and reducing NH3 gases. Different gas interaction model pathways were developed to describe the current flow mechanism through the sensing area.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Daria Miliaieva, Aurelien Sokeng Djoumessi, Jan Cermak, Katerina Kolarova, Maximilian Schaal, Felix Otto, Ekaterina Shagieva, Olexandr Romanyuk, Jiri Pangrac, Jaroslav Kulicek, Vojtech Nadazdy, Stepan Stehlik, Alexander Kromka, Harald Hoppe, Bohuslav Rezek
Summary: This study systematically investigates the structural and electronic properties of nanodiamonds (NDs) with different origins and surface terminations. By using optical and photoelectron spectroscopy, Kelvin probe measurements, and energy-resolved electrochemical impedance spectroscopy, the absolute energy level diagrams of NDs are obtained. The results show significant differences in energy band shifts, Fermi level position, electron affinity, optical band gap, band gap states, and electrical conductivity depending on the origin and surface modifications of NDs. These findings are crucial for understanding and designing the optoelectrochemical functional mechanisms of NDs in various application areas.
NANOSCALE ADVANCES
(2023)
