Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Growth promotion of vertical graphene on SiO₂/Si by Ar plasma process in plasma-enhanced chemical vapor deposition.

ABSTRACT: This study investigates the growth promotion of vertically oriented graphene in plasma-enhanced chemical vapor deposition through Ar plasma treatment. Combined with various substrate treatments, including hydrofluoric acid etching and oxidation after Ar plasma treatment, Ar plasma pretreatment promotes vertical growth through the microcavity on the rough substrate surface and the active growth sites. The microcavity affects the strain distribution and defects of as-deposited planar films, which benefit the transition of 2D deposition to 3D vertical growth. A growth model on the effect of Ar plasma pretreatment is proposed.

SUBMITTER: Sui Y

PROVIDER: S-EPMC9080714 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Growth promotion of vertical graphene on SiO2/Si by Ar plasma process in plasma-enhanced chemical vapor deposition.

Sui Yanping Y Chen Zhiying Z Zhang Yanhui Y Hu Shike S Liang Yijian Y Ge Xiaoming X Li Jing J Yu Guanghui G Yu Guanghui G Peng Songang S Jin Zhi Z Liu Xinyu X

RSC advances 20180522 34

This study investigates the growth promotion of vertically oriented graphene in plasma-enhanced chemical vapor deposition through Ar plasma treatment. Combined with various substrate treatments, including hydrofluoric acid etching and oxidation after Ar plasma treatment, Ar plasma pretreatment promotes vertical growth through the microcavity on the rough substrate surface and the active growth sites. The microcavity affects the strain distribution and defects of as-deposited planar films, which ...[more]

PMID: 35539632

Similar Datasets

The direct growth of planar and vertical graphene on Si(100) via microwave plasma chemical vapor deposition: synthesis conditions effects.

Project description:In the present research, graphene was synthesized directly on a Si(100) substrate via combining direct microwave plasma-enhanced chemical vapor deposition and protective enclosure. The graphene flake orientation was controlled using suitable synthesis conditions. We revealed that high processing temperatures and plasma powers promote vertical graphene growth. The main related physical mechanisms were raised temperature gradients, thermal stress, ion bombardment, and elevated electric field effects. Lowering the synthesis temperature and plasma power resulted in planar graphene growth. An elevated synthesis temperature and long deposition time decreased the graphene layer number as the carbon desorption rate increased with temperature. Dominating defect types and their relationships to the graphene growth conditions were revealed. Planar graphene n-type self-doping was found due to substrate-based charge transfer. In the case of vertical graphene, the increased contact area between graphene and air resulted in the adsorption of more molecules, resulting in no doping or p-type doping.

| S-EPMC9237919 | biostudies-literature

Insights into the Mechanism for Vertical Graphene Growth by Plasma-Enhanced Chemical Vapor Deposition.

Project description:Vertically oriented graphene (VG) has attracted attention for years, but the growth mechanism is still not fully revealed. The electric field may play a role, but the direct evidence and exactly what role it plays remains unclear. Here, we conduct a systematic study and find that in plasma-enhanced chemical vapor deposition, the VG growth preferably occurs at spots where the local field is stronger, for example, at GaN nanowire tips. On almost round-shaped nanoparticles, instead of being perpendicular to the substrate, the VG grows along the field direction, that is, perpendicular to the particles' local surfaces. Even more convincingly, the sheath field is screened to different degrees, and a direct correlation between the field strength and the VG growth is observed. Numerical calculation suggests that during the growth, the field helps accumulate charges on graphene, which eventually changes the cohesive graphene layers into separate three-dimensional VG flakes. Furthermore, the field helps attract charged precursors to places sticking out from the substrate and makes them even sharper and turn into VG. Finally, we demonstrate that the VG-covered nanoparticles are benign to human blood leukocytes and could be considered for drug delivery. Our research may serve as a starting point for further vertical two-dimensional material growth mechanism studies.

| S-EPMC8832395 | biostudies-literature

Chemical vapor deposition merges MoS2 grains into high-quality and centimeter-scale films on Si/SiO2.

Project description:Two-dimensional molybdenum disulfide (MoS2) has attracted increasing attention due to its promise for next-generation electronics. To realize MoS2-based electronics, however, a synthesis method is required that produces a uniform single-layer material and that is compatible with existing semiconductor fabrication techniques. Here, we demonstrate that uniform films of single-layer MoS2 can be directly produced on Si/SiO2 at wafer-scale without the use of catalysts or promoters. Control of the precursor transport through oxygen dosing yielded complete coverage and increased connectivity between crystalline MoS2 domains. Spectroscopic characterization and carrier transport measurements furthermore revealed a reduced density of defects compared to conventional chemical vapor deposition growth that increased the quantum yield over ten-fold. To demonstrate the impact of enhanced scale and optoelectronic performance, centimeter-scale arrays of MoS2 photosensors were produced that demonstrate unprecedentedly high and uniform responsivity. Our approach improves the prospect of MoS2 for future applications.

| S-EPMC8982092 | biostudies-literature

Influence of plasma treatment on SiO2/Si and Si3N4/Si substrates for large-scale transfer of graphene.

Project description:One of the limiting factors of graphene integration into electronic, photonic, or sensing devices is the unavailability of large-scale graphene directly grown on the isolators. Therefore, it is necessary to transfer graphene from the donor growth wafers onto the isolating target wafers. In the present research, graphene was transferred from the chemical vapor deposited 200 mm Germanium/Silicon (Ge/Si) wafers onto isolating (SiO2/Si and Si3N4/Si) wafers by electrochemical delamination procedure, employing poly(methylmethacrylate) as an intermediate support layer. In order to influence the adhesion properties of graphene, the wettability properties of the target substrates were investigated in this study. To increase the adhesion of the graphene on the isolating surfaces, they were pre-treated with oxygen plasma prior the transfer process of graphene. The wetting contact angle measurements revealed the increase of the hydrophilicity after surface interaction with oxygen plasma, leading to improved adhesion of the graphene on 200 mm target wafers and possible proof-of-concept development of graphene-based devices in standard Si technologies.

| S-EPMC8222355 | biostudies-literature

Electrically-triggered micro-explosion in a graphene/SiO2/Si structure.

Project description:Electrically-triggered micro-explosions in a metal-insulator-semiconductor (MIS) structure can fragment/atomize analytes placed on it, offering an interesting application potential for chip-scale implementation of atomic emission spectroscopy (AES). We have investigated the mechanisms of micro-explosions occurring in a graphene/SiO2/Si (GOS) structure under a high-field pulsed voltage drive. Micro-explosions are found to occur more readily in inversion bias than in accumulation bias. Explosion damages in inversion-biased GOS differ significantly between n-Si and p-Si substrate cases: a highly localized, circular, protruding cone-shape melt of Si for the n-Si GOS case, whereas shallow, irregular, laterally-propagating trenches in SiO2/Si for the p-Si GOS case. These differing damage morphologies are explained by different carrier-multiplication processes: in the n-Si case, impact ionization propagates from SiO2 to Si, causing highly-localized melt explosions of Si in the depletion region, whereas in the p-Si case, from SiO2 towards graphene electrode, resulting in laterally wide-spread micro-explosions. These findings are expected to help optimize the GOS-based atomizer structure for low voltage, small-volume analyte, high sensitivity chip-scale emission spectroscopy.

| S-EPMC5943326 | biostudies-literature

Selective isotropic etching of SiO2 over Si3N4 using NF3/H2 remote plasma and methanol vapor.

Project description:In this study, an isotropic etching process of SiO2 selective to Si3N4 using NF3/H2/methanol chemistry was investigated. HF was formed using a NF3/H2 remote plasma, and in order to remove the F radicals, which induces spontaneous etching of Si-base material, methanol was injected outside the plasma discharge region. Through this process, etch products were formed on the surface of SiO2, and then the (NH4)2SiF6 was removed by following heating process. When the H and F radicals were abundant, the highest SiO2 etch per cycle (EPC) was obtained. And, the increase of H2 and methanol percentage in the gas chemistry increased the etch selectivity by decreasing the F radicals. The etch products such as (NH4)2SiF6 were formed on the surfaces of SiO2 and Si3N4 during the reaction step and no noticeable spontaneous etching by formation of SiF4 was observed. By optimized conditions, the etch selectivity of SiO2 over Si3N4 and poly Si higher than 50 and 20, respectively, was obtained while having SiO2 EPC of ~ 13 nm/cycle. It is believed that the cyclic process using NF3/H2 remote plasma and methanol followed by heating can be applied to the selective isotropic SiO2 etching of next generation 3D device fabrication.

| S-EPMC10354158 | biostudies-literature

Catalyst-Less and Transfer-Less Synthesis of Graphene on Si(100) Using Direct Microwave Plasma Enhanced Chemical Vapor Deposition and Protective Enclosures.

Project description:In this study, graphene was synthesized on the Si(100) substrates via the use of direct microwave plasma-enhanced chemical vapor deposition (PECVD). Protective enclosures were applied to prevent excessive plasma etching of the growing graphene. The properties of synthesized graphene were investigated using Raman scattering spectroscopy and atomic force microscopy. Synthesis time, methane and hydrogen gas flow ratio, temperature, and plasma power effects were considered. The synthesized graphene exhibited n-type self-doping due to the charge transfer from Si(100). The presence of compressive stress was revealed in the synthesized graphene. It was presumed that induction of thermal stress took place during the synthesis process due to the large lattice mismatch between the growing graphene and the substrate. Importantly, it was demonstrated that continuous horizontal graphene layers can be directly grown on the Si(100) substrates if appropriate configuration of the protective enclosure is used in the microwave PECVD process.

| S-EPMC7763619 | biostudies-literature

Tunable graphene doping by modulating the nanopore geometry on a SiO2/Si substrate.

Project description:A tunable graphene doping method utilizing a SiO2/Si substrate with nanopores (NP) was introduced. Laser interference lithography (LIL) using a He-Cd laser (λ = 325 nm) was used to prepare pore size- and pitch-controllable NP SiO2/Si substrates. Then, bottom-contact graphene field effect transistors (G-FETs) were fabricated on the NP SiO2/Si substrate to measure the transfer curves. The graphene transferred onto the NP SiO2/Si substrate showed relatively n-doped behavior compared to the graphene transferred onto a flat SiO2/Si substrate, as evidenced by the blue-shift of the 2D peak position (∼2700 cm-1) in the Raman spectra due to contact doping. As the porosity increased within the substrate, the Dirac voltage shifted to a more positive or negative value, depending on the initial doping type (p- or n-type, respectively) of the contact doping. The Dirac voltage shifts with porosity were ascribed mainly to the compensation for the reduced capacitance owing to the SiO2-air hetero-structured dielectric layer within the periodically aligned nanopores capped by the suspended graphene (electrostatic doping). The hysteresis (Dirac voltage difference during the forward and backward scans) was reduced when utilizing an NP SiO2/Si substrate with smaller pores and/or a low porosity because fewer H2O or O2 molecules could be trapped inside the smaller pores.

| S-EPMC9078577 | biostudies-literature

Synthesis and photoluminescence properties of silica-modified SiO2@ANA-Si-Tb@SiO2, SiO2@ANA-Si-Tb-L@SiO2 core-shell-shell nanostructured composites.

Project description:Three novel core-shell nanostructured composites SiO2@ANA-Si-Tb, SiO2@ANA-Si-Tb-L (L = second ligand) with SiO2 as the core and terbium organic complex as the shell were successfully synthesized. The core and shell were connected together by covalent bonds. The terbium ion was coordinated with organic ligand-forming terbium organic complex in the shell layer. The organosilane (HOOCC5H4NN(CONH(CH2)3Si(OCH2CH3)3)2 (abbreviated as ANA-Si) was used as the first ligand and 1,10-phenanthroline (phen) or 2-thenoyltrifluoroacetone (TTA) was used as the second ligand. Furthermore, silica-modified SiO2@ANA-Si-Tb@SiO2, SiO2@ANA-Si-Tb-L@SiO2 core-shell-shell nanostructured composites were also synthesized by sol-gel chemical route, which involved the hydrolysis and polycondensation processes of tetraethoxysilane (TEOS) using cetyltrimethyl ammonium bromide (CTAB) as a surface-active agent. An amorphous silica shell was coated around the SiO2@ANA-Si-Tb, SiO2@ANA-Si-Tb-L core-shell nanostructured composites. The core-shell and core-shell-shell nanostructured composites exhibited excellent luminescence in the solid state. Meanwhile, an improved luminescent stability property of the core-shell-shell nanostructured composites was observed for the aqueous solution. This type of core-shell-shell nanostructured composites exhibited bright luminescence, high stability and good solubility, which may present potential applications in the fields of optoelectronic devices, bio-imaging, medical diagnosis and study on the structure of function composite materials.

| S-EPMC6731695 | biostudies-literature

Controlled synthesis and luminescence properties of core-shell-shell structured SiO2@AIPA-S-Si-Eu@SiO2 and SiO2@AIPA-S-Si-Eu-phen@SiO2 nanocomposites.

Project description:Two novel core-shell structured SiO2@AIPA-S-Si-Eu and SiO2@AIPA-S-Si-Eu-phen nanocomposites have been synthesized by a bifunctional organic ligands ((HOOC)2C6H3NHCONH(CH2)3Si(OCH2CH3)3) (defined as AIPA-S-Si) connected with Eu3+ ions and silica via covalent bond. And the corresponding core-shell-shell structured SiO2@AIPA-S-Si-Eu@SiO2 and SiO2@AIPA-S-Si-Eu-phen@SiO2 nanocomposites with enhanced luminescence have been synthesized by tetraethyl orthosilicate (TEOS) hydrolysis co-deposition method. The composition and micromorphology of the nanocomposites were characterized by means of Fourier-transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX) and X-ray photoelectron spectroscopy (XPS). The as-synthesized core-shell and core-shell-shell structured nanocomposites have excellent luminescence intensity and long lifetime. The nanocomposites show bright red light under ultraviolet lamp. However, the core-shell-shell structured nanocomposites have stronger luminescence intensity than the corresponding core-shell structured nanocomposites. Meanwhile, the core-shell-shell structured nanocomposites still exhibit good luminescence stability in aqueous solution. In addition, a large number of Si-OH on the surface of the core-shell-shell structured nanocomposites can be attached to many biomacromolecules. Therefore, they have potential applications in the fields of biology and luminescence.

| S-EPMC7044297 | biostudies-literature