Orientation Of Films Research Articles

Vertically Aligned One-Dimensional Crystal-Structured Sb2Se3 for High-Efficiency Flexible Solar Cells via Regulating Selenization Kinetics

Recently, antimony selenide (Sb2Se3) has exhibited an exciting potential for flexible photoelectric applications due to its unique one-dimensional (1D) chain-type crystal structure, low-cost constituents, and superior optoelectronic properties. The 1D structure endows Sb2Se3 with a strong anisotropy in carrier transport and a lasting mechanical deformation tolerance. The control of the crystalline orientation of the Sb2Se3 film is an essential requirement for its device performance optimization. However, the current state-of-the-art Sb2Se3 devices suffer from unsatisfactory orientation control, especially for the (001) orientation, in which the chains stand vertically. Herein, we achieved an unprecedented control of the (001) orientation for the growth of the Sb2Se3 film on a flexible Mo-coated mica substrate by balancing the collision rate and kinetic energy of Se vapor particles with the surface of Sb film by regulating the selenization kinetics. Based on this (001)-oriented Sb2Se3 film, a high efficiency of 8.42% with a record open-circuit voltage (VOC) of 0.47 V is obtained for flexible Sb2Se3 solar cells. The vertical van der Waals gaps in the (001) orientation provide favorable diffusion paths for Se atoms, which results in a Se-rich state at the bottom of the Sb2Se3 film and promotes the in situ formation of the MoSe2 interlayer between Mo and Sb2Se3. These phenomena contribute to a back-surface field enhanced absorber layer and a quasi-Ohmic back contact, improving the device's VOC and the collection of carriers. This method provides an effective strategy for the orientation control of 1D materials for efficient photoelectric devices.

Enhancement of electrical properties in Eu-doped PMN-PT thin films prepared by sol-gel method

Europium-modified Pb(Mg1/3Nb2/3)O3-0.32PbTiO3 (xEu-PMNT) (x = 1 %, 2 %, 3 %, 4 %) thin films have been deposited on Pt/Ti/SiO2/Si substrates via sol-gel process. The purpose of this present work was to investigate Eu doping-dependent crystal orientation, microstructure, and piezoelectric behaviors of the Eu-PMNT films. X-ray diffraction (XRD) analysis shows that PMNT films exhibit (100) preferred orientation when Eu content less than 3 %, and the film doped with 4 % show (110) polycrystalline orientation accompanied by pyrochlore phase. Increasing grain size and dense microstructure are detected by Scanning electron microscope (SEM) characterization as increasing Eu concentration to 2 %. For the film with 2 % Eu-doped, superior dielectricity (εr = 1204.5, tanδ = 0.055) measured at 1 kHz and ferroelectricity (2Pr = 21.6 μC/cm2, 2Ec = 73 kV/cm) are achieved. Moreover, an enhanced piezoelectric constant (e31) of 8.2 C/m2 is obtained in the PMN-PT film doped with 2 % Eu.

Proton conductivity in Yb-doped BaZrO3-based thin film prepared by pulsed laser deposition

For increasing the performance of PCFC (Protonic Ceramic Fuel Cells), it is important to prepare high-quality thin films of electrolyte materials. In this study, the preparation condition of the thin film of BaZr0.8Yb0.2O2.9 (BZYb) by pulsed laser deposition (PLD) method was optimized and the electrical conductivities of the obtained films were measured. The thin film was prepared by PLD using two kinds of BZYb targets, which were prepared by solids state reaction and Pechini method. Both thin-film samples have the single phase of the cubic perovskite-type structure, however, morphology as well as the orientation of the BZYb film was significantly different. The thin film using the target material by Pechini method is a high crystalline orientation and partially oriented [211] direction. The electrical conductivities of the obtained thin films at reduction atmosphere are dominated by proton conductivity, which is almost the same as that of the bulk sample despite [211] orientation.

Angular-dependent spin-wave modes observations and excitation origins in Yttrium iron garnet thin films

We present a study of the dynamic magnetic properties of sputtered-grown YIG films that were subsequently annealed at various temperatures. Our investigation involved the use of the ferromagnetic resonance technique enabled the observation of multimode spin waves spectra. A noticeable increase in the visibility of the multimode spin-wave modes was observed. This finding is ascribed to the rise in surface roughness and anti-site defects in our YIG films as the annealing temperatures increased. We analyzed the correlation between spin-wave modes and the orientation of the magnetic field H. Results showed that a spectrum made up of a variety of spin-wave modes is seen when the applied field H is normal to the film plane. Once the H is tilted from the normal, a critical angle of only one uniform precession mode was detected for some orientations. A fourfold symmetry of the resonance field emerges as H is in the film plane, ascribed to the anisotropy along different crystal orientations of YIG film. Finally, we were able to determine the exchange stiffness constant and distortion parameter by analyzing the spin waves resonance spectra.

Ultrafast RTA induced the structural properties of the deficient oxygen β-Ga2O3 film

The RF-sputtered β-Ga2O3 films prepared on sapphire substrates were treated by rapid thermal annealing (RTA) with an ultrafast processing time of 30 s. The effects of RTA at different process temperatures from 600 to 800 °C on the β-Ga2O3 films were researched. Meanwhile, the schematic diagram for the RTA-induced lattice expansion of films was proposed. The experimental results showed that the variation of Ga oxidation states and lattice oxygen was demonstrated, revealing a greater value of lattice oxygen at 700 °C. The (-201) orientation of Ga2O3 films is observed at 700 °C and 800 °C, where the (111) orientation additionally appeared at 800 °C. The larger grain size and interplanar distance of 4.71 Å for the (−201) orientation were also obtained at 700 °C, accounting for the high-quality β-Ga2O3 films and their lattice expansion. As a result, this RF-sputtered β-Ga2O3 films via the RTA process not only provide a new reference condition but also suitable for optoelectronic devices requiring control of crystallizing temperature and lattice variation.

Accelerated Sequential Deposition Reaction via Crystal Orientation Engineering for Low‐Temperature, High‐Efficiency Carbon‐Electrode CsPbBr3 Solar Cells

Low‐temperature, ambient processing of high‐quality CsPbBr3 films is demanded for scalable production of efficient, low‐cost carbon‐electrode perovskite solar cells (PSCs). Herein, we demonstrate a crystal orientation engineering strategy of PbBr2 precursor film to accelerate its reaction with CsBr precursor during two‐step sequential deposition of CsPbBr3 films. Such a novel strategy is proceeded by adding CsBr species into PbBr2 precursor, which can tailor the preferred crystal orientation of PbBr2 film from [020] into [031], with CsBr additive staying in the film as CsPb2Br5 phase. Theoretical calculations show that the reaction energy barrier of (031) planes of PbBr2 with CsBr is lower about 2.28 eV than that of (020) planes. Therefore, CsPbBr3 films with full coverage, high purity, high crystallinity, micro‐sized grains can be obtained at a low temperature of 150 °C. Carbon‐electrode PSCs with these desired CsPbBr3 films yield the record‐high efficiency of 10.27% coupled with excellent operation stability. Meanwhile, the 1 cm2 area one with the superior efficiency of 8.00% as well as the flexible one with the champion efficiency of 8.27% and excellent mechanical bending characteristics are also achieved.

Investigating the properties of nickel oxide thin films prepared via DC reactive magnetron sputtering for potential application in gas sensing

Nanocrystalline nickel oxide (NiO) thin films were developed on Si substrate using DC reactive magnetron sputtering. The goal of our study was to investigate the impact of O2/Ar gas ratios (varied from 10% to 20%) on the properties of sputtered NiO thin films. Further, after the deposition, all the samples were annealed at 400 ℃ in air. The prepared thin films were characterized by GIXRD, UV–visible spectroscopy, and FESEM to investigate the structural, optical, and morphological properties, respectively. The GIXRD results demonstrated the formation of the polycrystalline nature of sputtered NiO films with the FCC phase. As the O2 ratio was increased, the preferred orientation of NiO thin film was found to change from (111) to (200) plane with an average crystallite size of ∼ 14 nm. The UV–visible spectroscopy measurements show the semi-transparent nature of the deposited NiO films with a decreasing trend in the transmittance value from ∼ 83% to ∼ 77% with an increase in the O2 to Ar gas ratio. This behavior could be due to the poor crystallization of the film. However, the change in the calculated band gap of NiO films with respect to O2 partial pressure was found to be negligible and lay between 3.82 eV and 3.84 eV. The surface morphology was studied using FESEM, which depicted the uniform and homogenous distribution of grains with cracks on the film that improve the gas permeability; hence it may prove beneficial for gas sensing applications. Besides, the observed contact angle, as measured by the wettability test for the NiO films at different oxygen partial pressure, was greater than 90°, which shows that all the deposited NiO thin films are hydrophobic. Additionally, we have tested the CO gas sensor responses of the NiO sample deposited at a 15% O2/Ar ratio due to the high hydrophobic nature among all three ratios.

Lamellar orientation at the surface of isotactic polystyrene thin films analyzed by sum frequency generation spectroscopy.

Analyzing the orientation of polymeric crystalline lamella at the surface of thin films can be challenging. Even though atomic force microscopy (AFM) is often sufficient for this analysis, there are cases when imaging is not sufficient to confidently determine lamellar orientation. Here, we used sum frequency generation (SFG) spectroscopy to analyze the lamellar orientation at the surface of semi-crystalline isotactic polystyrene (iPS) thin films. The SFG orientation analysis indicated that the iPS chains are oriented perpendicular to the substrate (flat-on lamellar orientation), which was confirmed by AFM. By analyzing the evolution of the SFG spectral features with the progress of crystallization, we demonstrated that the ratios of the SFG intensities of the phenyl ring resonances are a good indication of the surface crystallinity. Furthermore, we explored the challenges associated with SFG measurements of heterogeneous surfaces, which is commonly present in many semi-crystalline polymeric films. To the best of our knowledge, this is the first time that the surface lamellar orientation of semi-crystalline polymeric thin films was determined by SFG. Also, this work pioneers in reporting the surface conformation of semi-crystalline and amorphous iPS thin films by SFG and in linking the SFG intensity ratios to the progress of the crystallization and the surface crystallinity. This study demonstrates the potential applicability of SFG spectroscopy in the conformational analysis of polymeric crystalline structures at interfaces and opens the way to the investigation of more complex polymeric structures and crystalline arrangements, especially for the case of buried interfaces, where AFM imaging is not an option.

Air and Vacuum Annealing Effect on the Highly Conducting and Transparent Properties of the Undoped Zinc Oxide Thin Films Prepared by DC Magnetron Sputtering

In this study, we aim to investigate the effect of zinc interstitials (Zni) and oxygen vacancies (VO) on the ZnO electrical conductivity. ZnO films were synthesized via DC magnetron sputtering process using pure Zn target in gases mixture of Ar/O2 = 80/17.5 (sccm). In order to improve the optical and electrical prosperities, the obtained films were subjected to air and vacuum annealing treatment. Several techniques such as field emission scanning electron microscopy (FESEM), Grazing Incidence X-ray Diffraction (GIXRD), Raman spectroscopy, photoluminescence spectroscopy (PL) and UV-visible were used to study the influence of heat treatment on structural and physical properties of ZnO films. Electrical conductivity of ZnO thin films was determined by measuring the sheet resistance and thickness of the films. XRD results confirm the synthesis of annealed ZnO films of the hexagonal structure with a preferential orientation along the (002) plane. The average crystallite size is altered between 22.6 to 28.4 nm dependent on the plan orientation of the ZnO film. Morphology and crystallinity of the ZnO structure could efficiently control the transmittance, electrical resistivity and optical band gap. As deposited ZnO film showed a lower electrical resistivity of 2.72×10-3 Ωcm due to the Zn-rich conditions. Under vacuum annealing, a combination of low resistivity (1.17×10-2 Ωcm) and better optical transmittance (87 %) are obtained. ZnO films developed in this study with high transmittance and low resistivity and good electro-optical quality supports their use in transparent and conductive electrode applications. The plan presentation was visualized using Vesta, with the lattice parameter set as follows: a = b = 3.249 Å; c = 5.207 Å; α = β = 90°; γ = 120°. Based on the construction and optimization of primitive cells, the supercells were constructed and then optimized. Finally, (002) and (103) planes were cut and the planar supercell structure was constructed. In order to make a plane representation for the solid bulk with 10 Å of thickness.

Laterally Grown Strain-Engineered Semitransparent Perovskite Solar Cells with 16.01% Efficiency

Hybrid organometallic halide perovskite-based semitransparent solar cell research has garnered significant attention recently due to their promising applications for smart windows, tandem devices, wearable electronics, displays, and sustainable internet-of-things. Though considerable progress has been made, stability, controlling the crystalline qualities, and growth orientation in perovskite thin films play crucial roles in improving the photovoltaic (PV) performance. Recently, strain modulation within the perovskite gathers an immense interest that is achieved by the ex situ process. However, little work is reported on in situ strain modulation, which is presented here. Apart from the challenges in the fabrication of high-efficiency perovskite solar cell (PSC) devices under ambient conditions, the stability of organic hole-transporting materials needs urgent attention. Herein, a single-step deposition of formamidiniumchloride (FACl)-mediated CH3NH3PbI3 (MAPbI3) thin films without an inert atmosphere and CuI as the inorganic hole-transporting material is demonstrated for their potential application toward semitransparent PSCs. The FACl amount in MAPbI3 (mg/mL) plays a critical role in controlling the crystallinity, growth orientations, and in situ strains, which modulate the charge carrier transport dynamics, thereby improving the efficiency of the PSC device. A photoconversion efficiency of 16.01% has been achieved from MAPbI3 with 20 mg/mL of FACl additive incorporation. The modification of the structural, electronic, and optical properties and the origin of strain in the as-synthesized MAPbI3 domains due to the addition of FACl are further validated with experimental findings in detail using density functional theory simulations.

Epitaxy growth of pure phase CeFeO3 thin films with high magneto-optical performance and strong vertical magnetic anisotropy

The magneto-optical effects of rare earth ferrite can be greatly improved by doping Ce3+ ions. CeFeO3 with high Ce3+ concentration has excellent magneto-optical properties in theory. And due to its perovskite structure it is more suitable to be deposited on the substrates of optical devices compared with the commercial garnet ferrite. In this paper, the pure phase CexFe2–xO3 films were successfully obtained on the quartz glass and <100>-oriented SrTiO3 crystal substrates by radio frequency magnetron sputtering. The effects of substrate and Ce:Fe ratio on the epitaxial orientation, magnetism and magneto-optical performance of films were systematically studied. For the Ce1.0Fe1.0O3/STO film, its MCD ellipticity (ψF) intensity can reach up to 4750(°)/cm in the visible band and 14090(°)/cm in near ultraviolet band. And it also shows a strong vertical magnetic anisotropy, which makes it maintain a good thermal stability when the device size is reduced. These mean that the Ce1.0Fe1.0O3/STO film has a promising application in integrated optical communication devices.

Rational Regulation of Organic Spacer Cations for Quasi‐2D Perovskite Solar Cells

Quasi‐two‐dimensional perovskite solar cells (quasi‐2D PSCs) have drawn significant attention and are rapidly developing owing to the impressive stability of the materials and devices. However, there are no reliable guidelines for designing and selecting suitable organic spacer cations to achieve high power conversion efficiency (PCE) in quasi‐2D PSCs. Herein, the effects of the spacer cations with different substituents, i.e., benzylamine (PMA), 4‐methoxybenzylamine (p‐MeOPMA), and 4‐fluorobenzylamine (p‐FPMA), on the optoelectronic properties and device performance of quasi‐2D perovskites are systematically investigated. It is found that the spacer cations with different substituents mainly affect the crystal growth and film quality of quasi‐2D perovskites. Interestingly, quasi‐2D perovskites based on p‐MeOPMA or p‐FPMA exhibit poor crystallinity and crystal orientation, while quasi‐2D perovskite based on the unsubstituted PMA shows improved crystallinity and crystal orientation, which enables suppressed trap densities and efficient charge transport. The PMA‐based quasi‐2D perovskite (nominal n = 3) solar cell exhibits the highest PCE of 13.58%. These results demonstrate that the rational regulation of organic spacer cations plays a crucial role in improving the crystallinity and crystal orientation of perovskite films and elucidate key guiding rules for organic spacer cations for high‐performance quasi‐2D PSCs.

Synergistic Crystallization Modulation and Defects passivation via Additive Engineering Stabilize Perovskite Films for Efficient Solar Cells

AbstractOrganic‐inorganic lead halide perovskite are promising photovoltaic materials, but their intrinsic defects and crystalline quality severely deteriorate the solar cells efficiency and stability. Herein, potassium 1,1,2,2,3,3‐hexafluoroprop‐ane‐1,3‐disulfonimide (KHFDF) is introduced into PbI2 precursor solution to passivate various defects and improve the crystalline quality of perovskite films. It is found that KHFDF can inhibit PbI2 crystallization, thus tuning the crystal orientation and growth of perovskite films. Furthermore, KHFDF with dual‐functional sulfonyl group cannot only passivate grain boundaries (GBs), but also passivate the defects at GBs via strong interaction with undercoordinated Pb2+ and/or hydrogen bonding with FA+, while the K+ counter cations allow ionic interaction with undercoordinated I−. As a result, the KHFDF‐modified films exhibit high quality with a larger grain size and a reduced trap‐state density, thereby suppressing the trap‐state nonradiative recombination. And the devices show a champion efficiency up to 24.15%, benefiting from a sharp enhancement of open‐circuit voltage (Voc) of 1.183 V and fill factor of 81.78%. In addition, due to the enhanced humidity tolerance and chemical structure stability, the devices exhibit excellent long‐term humidity and thermal stability without encapsulation.

Effects of primary, secondary and tertiary structures on functional properties of thermoplastic starch biopolymer blend films

To better understand the correlation between structure and properties in thermoplastic starch biopolymer blend films, the effects of amylose content, chain length distribution of amylopectin and molecular orientation of thermoplastic sweet potato starch (TSPS) and thermoplastic pea starch (TPES) on microstructure and functional properties of thermoplastic starch biopolymer blend films were studied. After thermoplastic extrusion, the amylose contents of TSPS and TPES decreased by 16.10 % and 13.13 %, respectively. The proportion of the chains with the degree of polymerization between 9 and 24 of amylopectin in TSPS and TPES increased from 67.61 % to 69.50 %, and from 69.51 % to 71.06 %, respectively. As a result, the degree of crystallinity and molecular orientation of TSPS and TPES films increased as compared to sweet potato starch and pea starch films. The thermoplastic starch biopolymer blend films possessed a more homogeneous and compacter network. The tensile strength and water resistance of thermoplastic starch biopolymer blend films increased significantly, whereas thickness and elongation at break of thermoplastic starch biopolymer blend films decreased significantly.

Strong, anisotropic, layer-independent second harmonic generation in multilayer SnS film.

Materials based on group IV chalcogenides exhibit extensive technologically important properties. Its unusual chemical bonding and off-centering of in-layer sublattices could cause chemical polarity and weakly broken symmetry, making optical field controlling feasible. Here, we fabricated large-area SnS multilayer films and observed unexpected strong SHG response at 1030 nm. The appreciable SHG intensities were obtained with an independence on layer, which is opposite to the generation principle of overall nonzero dipole moment only in odd-layer material. Taking GaAs for reference, the second-order susceptibility was estimated to be 7.25 pm/V enhanced by mixed-chemical bonding polarity. Further polarization-dependent SHG intensity confirmed the crystalline orientation of SnS films. The results imply surface inversion symmetry broken and nonzero polarization field modified by metavalent bonding should be the origin of SHG responses. Our observations establish multilayer SnS as a promising nonlinear material, and will guide in design of IV chalcogenides with improved optics and photonics properties for the potential applications.

Effect of polyethylene glycol molecular weight on the electrodeposition of nanostructured nickel

Electrodeposition is an attractive approach to synthesize nanostructured metals and their microstructure can be effectively controlled by tuning the process parameters. Here, two molecular weight (MW) types of polyethylene glycol (PEG) were used as additives for nickel electrodeposition in Watts bath. The surface morphology, crystal orientation, microstructure and microhardness of the Ni film were investigated. Experimental results revealed that the MW of PEG played a decisive role in controlling the microstructure of the deposits. As the current density increased from 25 to 100 mA/cm2, the microstructure of the Ni film deposited from the PEG600-containing bath evolved from ultrafine grains with nanotwin lamella perpendicular to the substrate surface to randomly oriented nanotwins, where the average grain size decreased from 118 nm to 78 nm. Within the same current density range, the Ni film obtained from the PEG10000-containing bath presented fine nanograins with multifold nanotwins (e.g., fivefold nanotwins) in random orientations with the average grain sizes of around 10 nm, little influenced by the current density. Such microstructure transition could be attributed to that the addition of PEG facilitated the formation of twins, and higher MW PEG induced a greater inhibition effect, promoting significant grain refinement.

Template-free self-assembly of mesoporous ZnO nanocluster/ polymethyl methacrylate based anisotropic nanocomposite thin films with enhanced interfacial interactions and tuneable optical properties

Nature inspired biomimetic growth of anisotropic, hierarchical nanostructures could offer insight into new and exciting crystalline properties for advanced multifunctional applications. Our study demonstrates diethanolamine-mediated mesoscopic self-assembly of semiconducting ZnO Quantum Dots (3–5 nm) into lattice-aligned, symmetrical superstructures (40–50 nm) via non-classical oriented attachment (OA) crystal growth observed in various biomineralization processes. Multifunctional nanocomposite thin films of self-assembled nanostructures and polymethyl methacrylate were spin-coated onto plasma-treated Si wafers and the surface and interfacial properties were rigorously studied. HR-TEM images depicted the OA growth process with neighboring nano-crystals having perfectly aligned lattices. Preferential orientation of the thin films along <100> direction was evident from the XRD data. Quantum confinement in ZnO QDs and surface defect originating sharp green PL emission were examined through UV–Vis absorption and Photoluminescence spectra respectively. DLS and Zeta potential studies of surface-engineered colloidal superstructures established excellent long-term physico–chemical stability with no agglomeration or transparency loss observed in ZnO mesocrystal suspension even after 6 months. Diethanolamine, due to its dual functionality radically enhanced the interaction between polar ZnO and non-polar PMMA matrix resulting in highly stable thin films (Class II hybrids) with enhanced surface and interfacial properties as evident from the extremely low surface roughness and homogenous nanofiller dispersion observed in AFM and FE-SEM studies. Chemical interactions at the interface were also established quantitatively by XPS binding energy measurements which suggested hydrogen bonds and covalent bonds between organic-inorganic phases promoted via diethanolamine surface engineering.

Orientation Engineering via 2D Seeding for Stable 24.83% Efficiency Perovskite Solar Cells

AbstractOrganic‐inorganic hybrid perovskite solar cells (PSCs) have been extensively researched as a promising photovoltaic technology, wherein the orientation of the perovskite film plays a crucial role in the power conversion efficiency (PCE) and stability. Here, a seed‐mediated method is developed to in situ grow a layer of 2D perovskite seed for epitaxial growth of 3D perovskite atop it to construct a high‐quality 2D/3D heterojunction. It is found that the epitaxial 3D perovskite film exhibits a preferred [112] direction, which is different from traditional perovskites with a preferred [001] orientation. The oriented perovskite film consists of large‐sized grains with low defect density, long charge‐carrier lifetime, and good stability, resulting in efficient PSCs with a champion efficiency of 24.83%. In addition, the devices exhibit high stability under ambient, thermal, and continuous light‐soaking conditions. This work provides an effective strategy for achieving high‐quality perovskite films with tunable orientation to simultaneously boost the efficiency and stability of PSCs.

Effect of chromium doping on the structure and mechanical properties of anti-wear TiB2 coatings

TiB2-based coatings have been intensively developed due to their physical and mechanical properties, including excellent thermal stability and high hardness with good abrasion and corrosion resistance, which appear to be the most beneficial in industrial application. Previous investigations have shown that doping TiB2 with W, Ni and C can significantly reduce residual stresses and improve adhesion, making these coatings ideal on tools to machining aluminum alloys. The aim of this study was to analyze the effect of an Cr interlayer on the durability (adhesion) of the fabricated Ti1−xCrxB2 (x = 0; 0.03; 0.06; 0.10) films and determine the influence of Cr on their microstructure and mechanical properties. The structural characterization of Ti1−xCrxB2 coatings was carried out using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and atomic force microscopy. To investigate the mechanical properties, nano-scratch and—hardness tests (NST, NHT) were performed, and fracture toughness of the substrate layer systems was determined. The use of an adhesive layer of pure Cr increased the adhesion of the coatings to the substrate. It is shown that the changes in Cr content not only affect the microstructure, mainly by decreasing the crystallite size (column width), but also the texture (preferred film orientation) and phase composition. The addition of chromium also has an effect on the mechanical properties of TiB2 films by reducing their hardness and Young’s modulus and increasing their fracture toughness (KIC).

CVD Diamond Growth Enhanced by a Dynamic Magnetic Field

A dynamic magnetic field (DMF) with different angular frequencies (50, 100, and 150 π rad/s) was introduced during diamond growth via hot filament chemical vapor deposition (HFCVD). The effects of the dynamic magnetic field on the growth rate, diamond quality, growth orientation, and deposition uniformity of large-area diamond films were investigated with scanning electron microscopy (SEM), X-ray diffractometry (XRD), and Raman spectroscopy. The correlation between diamond growth and angular frequency was discussed. The results showed that a faster growth rate (about 2.5 times) and higher diamond quality were obtained by increasing the angular frequency of the DMF. A (100) textured polycrystalline diamond film was achieved, and the preferential orientation was found to evolve from (110) to (100), while the expected uniform deposition of a large-area diamond film under DMF was not achieved. The enhancement effect of the DMF was ascribed to the activation of more gas molecules, which participated in CVD diamond growth.