Boron-doped Diamond Substrate Research Articles

Three-dimensional porous SiC/BDD electrode with long-term robustness and enhanced electrochemical degradation performance for refractory organic pollutants

Boron-doped diamond (BDD) electrodes with a three-dimensional (3D) porous network structure can overcome the mass transfer limitations and increase substantially the utilization rate of active oxygen species. Nonetheless, the 3D porous network structure was invariably built using metallic substrates, which inherently have inferior stability because of their non-corrosion resistance and the severe thermal mismatch between BDD films and substrates. Herein, we reported, for the first time, the use of a commercially porous silicon carbide (SiC) as the substrate to construct a 3D SiC/BDD electrode to simultaneously alleviate the problematics of substrate corrosion and thermal mismatch. This novel electrode exhibited a long-term service lifetime of 800 h in 3 M H2SO4 under the current density of 50 mA cm−2, over 500 times longer than the conventional metallic substrate-based BDD electrodes. The optimum p-SiC/BDD electrode exhibited a high oxygen evolution potential of 2.04 V vs. SHE, a low charge transfer resistance of 18.4 Ω, a high mass transfer coefficient of 2.78 × 10−5 m s−1, and a thin diffusion layer thickness of 25.2 μm. The proposed electrode had a threefold larger pseudo-first-order reaction rate constant than a flat BDD electrode, although it consumed just a fourth of the latter’s electric energy. The superior performance was attributable to an increased mass transfer rate confirmed by computational fluid dynamics (CFD) simulations as well as a high yield of reactive oxygen species verified by electron spin resonance (ESR). Furthermore, the proposed SiC/BDD electrode could work effectively under different water matrices in the presence of diverse salt electrolytes, thus paving a new avenue for the structure design of robust non-active anode materials.

Boron-doped diamond composites for durable oxygen evolution

The urgent need to develop efficient, durable, and cost-effective oxygen evolution reaction (OER) catalysts for energy conversion and storage has prompted extensive research. Currently available commercial noble metal-based OER catalysts are expensive and exhibit limited long-term stability. In this study, boron-doped diamond composites (BDDCs) consisting of CoFe and CoFe2C nanoparticles supported by boron-doped diamond (BDD) particles have been prepared. The BDDC catalyst, prepared through a straightforward annealing process, exhibits exceptional durability (up to 72 h at 10 mA cm−2), a low overpotential (306 mV at 10 mA cm−2), and modest Tafel slope (58 mV dec-1). The coherent interfaces between CoFe/CoFe2C nanoparticles and the BDD substrate are essential for enhancing the OER performance. The fabrication method and composite structures presented in this study may facilitate the design and production of promising catalysts.

Confined PbO2 nanoparticles in carbon nanotubes on boron-doped diamond substrate for highly efficient chlortetracycline degradation

Realizing highly efficient catalysis with high stability in complex chemical environments remains a major challenge for advanced oxidation processes. Here, confined lead dioxide (PbO2) nanoparticles in carbon nanotubes (CNTs) on boron-doped diamond (BDD) substrate is designed and fabricated as a heterogeneous catalyst for antibiotic treatment, achieving ultra-efficient degradation of chlortetracycline (CTC) with high reaction rate and stability. The maximum degradation rate of CTC reaches 98.8 % in 120 min, and it remains 91.0 % after ten cycles, which are significantly higher than that proposed by the contrast catalysts. The excellent degradation performance of this heterogeneous catalyst is mainly attributed to three factors: (i) the prepared PbO2 nanoparticles with an average size of 5 nm are confined in CNTs, providing more active sites and higher electron transfer rate; (ii) secondary pollution and catalyst deactivation of PbO2 are avoided by protecting CNTs; (iii) BDD shows strong capacity for mineralizing organic compounds related to the high oxygen evolution reaction potential. This finding provides a novel strategy for advanced oxidation processes in environmental remediation.

Use of Boron Doped Diamond Corrosion Free Supports to Evaluate Fuel Cell Electrocatalyst Stability Under Accelerated Stress Testing

Proton exchange membrane fuel cell (PEMFC) electrocatalysts are typically Pt or Pt alloy nanoparticles (NPs) supported on high surface area carbon black powders, the latter which contain a significant sp2 carbon component. One of the barriers to PEMFC commercialisation is the lifetime of the catalyst-support system, which should be at least 5,000 hours for automotive applications.[1] During the start-up and shut-down of the PEMFC, the cathode is subjected to significant oxidative potentials (greater than 1 V vs RHE) which can lead to corrosion of the predominantly sp2 bonded carbon support, a key factor which can limit the lifetime of PEMFCs. [2] High quality boron doped diamond (BDD) is an sp3 bonded network with above 1:1000 B:C ratio, which is required for metal-like electronic conductivity. BDD has many favourable properties for electrochemical experiments, most notably: higher electrochemical corrosion resistance with respect to sp2 carbons, low background currents, and a wide aqueous solvent window.[3] In this work we first explore the electrochemical corrosion stability of BDD when undergoing electrochemical cycling in acid solutions. To achieve this BDD substrates (BDD TEM grid) suitable for both electrochemical experiments and high magnification (single atom resolution) transmission electron microscopy (TEM) experiments were produced using precision ion polishing (Gatan PIPS-II). The surface was characterised using X-ray photoelectron spectroscopy to ensure the polishing process did not significantly alter the diamond substrate. Under aggressive electrochemical potential cycling in perchloric acid and sulfuric acid solutions, both TEM morphological analysis and Electron Energy Loss Spectroscopy (EELS) thickness measurements showed no evidence of BDD corrosion. [4] The BDD-TEM substrate was then used as a platform for investigating the degradation of a PEMFC electrocatalyst (Pt NPs) under accelerated stress testing (AST) [1] conditions on an atomic level, using the corrosion free carbon support. This enables the influence of other degradation pathways [2] (such as aggregation, Ostwald Ripening & direct dissolution) to be explored in more detail, free from issues associated with corrosion of the support. Pt NPs, in the size range 1 – 4 nm, were sputter coated onto the BDD TEM grid. Identical location ex-situ TEM (IL-TEM)[5] in combination with image analysis was used to probe NP changes e.g. size, shape, position, on an individual basis before, and after, AST (Fig. 1, which contains c.a. 200 NPs for analysis). Such measurements were complemented by Inductively Coupled Plasma – Optical Emission Spectroscopy analysis for any dissolved Pt, and electrochemical cyclic voltammetry measurements of the Pt to highlight changes in electrocatalytic behaviour (hydrogen evolution reaction and oxygen reduction reaction) due to AST cycling.Figure 1 – High magnification annular dark field (ADF) identical location images of Pt NPs, a) Pt/BDD before AST, b) Pt NPs after AST, c) Cyclic voltammogram of the 1000 cycle AST from 0.8 to 1.4 V vs Ag|AgCl (1.6 to 1.6 V vs RHE).

Nucleation of cubic boron nitride on boron-doped diamond via plasma enhanced chemical vapor deposition

Cubic boron nitride (c-BN), with a small 1.4% lattice mismatch with diamond, presents a heterostructure with multiple opportunities for electronic device applications. However, the formation of c-BN/diamond heterostructures has been limited by the tendency to form hexagonal BN at the interface. In this study, c-BN has been deposited on free standing polycrystalline and single crystal boron-doped diamond substrates via electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD), employing fluorine chemistry. In situ x-ray photoelectron spectroscopy (XPS) is used to characterize the nucleation and growth of boron nitride (BN) films as a function of hydrogen gas flow rates during deposition. The PECVD growth rate of BN was found to increase with increased hydrogen gas flow. In the absence of hydrogen gas flow, the BN layer was reduced in thickness or etched. The XPS results show that an excess of hydrogen gas significantly increases the percent of sp2 bonding, characteristic of hexagonal BN (h-BN), particularly during initial layer growth. Reducing the hydrogen flow, such that hydrogen gas is the limiting reactant, minimizes the sp2 bonding during the nucleation of BN. TEM results indicate the partial coverage of the diamond with thin epitaxial islands of c-BN. The limited hydrogen reaction is found to be a favorable growth environment for c-BN on boron-doped diamond.

Laser‐Engraved Boron‐Doped Diamond for Copper Catalyzed Non‐Enzymatic Glucose Sensing

AbstractRobust and high‐performance electrochemical electrodes for non‐enzymatic glucose sensing are in constant demand. Herein, a hierarchical nonenzymatic glucose sensing electrode on boron‐doped diamond (BDD) is fabricated using high‐speed laser engraving and pulsed electrodeposition of Cu nanostructures. The obtained electrode contains a densely packed Cu nanoflake (CuNF) array periodically decorated on the laser‐engraved BDD. The hierarchical nanoarchitecture combines the d‐band catalytic activity of the CuNFs with the low capacitive background current of the engraved BDD substrate, thus enabling fast, precise, and high signal‐to‐noise ratio detection of trace glucose. Outstanding performances that combine high sensitivity of 2119 µA cm–2 mm–1, ultrafast response time of <1 s, and low detection limit of 0.2 × 10−6 m are experimentally demonstrated. Furthermore, the electrode exhibits excellent cyclicality and anti‐interference ability, and maintains 90% of its initial responsivity after being stored in air for >8 months, indicating great stability for practical usage.

Improved NH3-N conversion efficiency to N2 activated by BDD substrate on NiCu electrocatalysis process

We developed a novel boron-doped diamond (BDD) electrode by the modification of bimetallic NiCu catalysts via electrochemical co-deposition method for improving the NH3-N conversion efficiency and selectivity to N2 in aqueous solution. It shows that the N2 selectivity of ammonia oxidation reaction (AOR) reached 88.62% with the NH3-N oxidation efficiency of 44.8% in 6 h. The high current efficiency of 84.17% was achieved at 1.2 V (vs Ag/AgCl), and the energy consumption was 8.19 kW·h/(kgN). Furthermore, the reaction mechanism has been investigated by in-situ Raman spectra, X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) during the reaction. It is verified that the BDD substrate plays a crucial role not only in the improvement of electronic transmission rate and but also the generation of abundant hydroxyl radicals (·OH) which provide proper hydrogen acceptors for the N-H bond activation processes. Theoretical calculations further reveal the doping effect of Cu(OH)2 with NiOOH that constructs the Cu/Ni concerted metal-nitrogen interaction, which stabilizes the relative energies of the intermediates thus promoting the reaction. This work sheds new light on the mechanism of selective electrochemical oxidation of NH3-N and develops an innovative technology of catalytic anode design toward wastewater treatment.

Polychlorinated Biphenyl Electrochemical Aptasensor Based on a Diamond-Gold Nanocomposite to Realize a Sub-Femtomolar Detection Limit.

Polychlorinated biphenyls (PCBs) with high toxicity, low lethal dose, and bioaccumulation have been inhibited for application in wide fields, and a highly efficient trace detection is thus greatly desirable. In this study, we produce dense Au-nanoparticles by twice sputtering and twice annealing (T-Au-NPs) on boron-doped diamond (BDD). The successful formation of T-Au-NPs/BDD nanocomposites was confirmed by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy analysis. Based on T-Au-NPs/BDD, an electronic biosensor with aptamers is fabricated to detect trace polychlorinated biphenyl-77 (PCB-77) by electrochemical impedance. A good linear relationship in the range of femtomolar to micromolar and significantly low detection limit of sub-femtomolar level (0.32 fM) are realized based on the biosensor. The emphasis of this research lies in the key role of the diamond substrate in the biosensor. It is demonstrated that the biosensor has excellent sensitivity, specificity, stability, and recyclability, which are favorable for detecting the trace PCB-77 molecule. It is attributed to the important effect presented by the BDD substrate and the synergistic influence of T-Au-NPs combined with aptamers.

Effect of americium‐241 source activity on total conversion efficiency of diamond alpha‐voltaic battery

High-quality diamond intrinsic layer was epitaxially grown on a IIb-type boron-doped diamond substrate. The quality of the epitaxy layer was evaluated by Raman spectroscopy and cross-polarizer images and compared with other samples. The dark current of the diode was analyzed, revealing a rectification ratio as high as 2 × 109 at ±7 V. Current-voltage characteristics of the converter under the irradiation of different americium-241 activity sources were investigated. A maximum total conversion efficiency (ηtotal) of 1.41%, short-circuit current (Isc) of 6.68 nA/cm2, and open-circuit voltage (Voc) of 1.06 V from the diamond alpha-voltaic battery were obtained under the irradiation of an americium-241 source with a source activity of 8.85 μCi/cm2. The trend for the battery parameters with the increase in the activity of the americium-241 source was clarified. Parameters Isc and Voc increase with the increase in the radioactive source activity. The ηtotal increases with the increase in the source activity but fluctuates in a certain activity interval with an increase in the fill factor, and then decreases with the increase in radioactive source activity. The research results are significant for the design of nuclear batteries.

Electro-Precipitation of Actinides on Boron-Doped Diamond Thin Films for Solid Sources Preparation for High-Resolution Alpha-Particle Spectrometry

In this work, we investigate a novel approach to prepare high-performance alpha-particle solid sources fabricated on diamond thin support layers, offering the properties of diamond such as a low-Z material with corrosion and mechanical hardness. As-prepared solid sources onto boron-doped-diamond (BDD) substrate exhibited high performance of the autoradiography and spectroscopic resolution at the level of other more conventional materials such as stainless steel. A straightforward precipitation process in the Na2SO4 or NaNO3 simple electrolytes under mild experimental conditions with a low current of several mA.cm−2 were successfully developed onto BDD substrates for deposition of single 241Am as well as 239Pu, 241Am, and 244Cm mixed radionuclides. The results demonstrate that solid sources deposited onto such BDD substrates can match the performance of those prepared onto stainless steel substrates with excellent uniformity and high-resolution spectroscopy, together combining the robustness, chemical resilience, and X-ray transparence of the diamond. Alpha-particle spectra exhibiting a low full width at half maximum (FWHM) of 12.5 keV at the energy of 5.485 MeV (241Am) could be practically obtained for BDD substrates.

Electrodeposition of Cuprous Oxide on Boron Doped Diamond Electrodes

Nowadays, Cu_2O is very promising electrode material for photoelectrochemical applications. In this paper, we report on the controllable synthesis of Cu_2O single particles as well as compact layers on Boron Doped Diamond (BDD) electrodes using potentiostatic deposition in continuous and pulse mode. The BDD layers were prepared with different B/C ratios in the gas phase in order to investigate boron doping level influence on the Cu_2O properties. The effect of electrodeposition conditions such as deposition regime and pulse duration was investigated as well. The Cu_2O covered BDD electrodes were analysed by Scanning Electron Microscopy (SEM) and Raman spectroscopy. Improvement in the homogeneity of the electrodeposit and removal of clusters were achieved when the pulse potentiostatic regime was used. Using the same pulse electrodeposition parameters, we confirmed the possibility of controlling the deposition rate of Cu_2O by varying the BDD conductivity. Finally, we were able to scale the size of Cu_2O particles by changing the number of deposition pulses. The obtained results have shown a great potential of controlling the morphology, amount, size and distribution of Cu_2O films on BDD substrates by changing the boron doping level and electrodeposition conditions as well. The investigations reported herein allowed us to better understand the deposition mechanism of Cu_2O on BDD electrodes which could then be used for preparation of active layers for electrochemical applications and in optoelectronic devices such as solar cells and photodetectors.

Semiconductor SERS of diamond.

In this work, we report a favorable diamond substrate to realize semiconductor surface-enhanced Raman spectroscopy (SERS) for trace molecular probes with high sensitivity, stability, reproducibility, recyclability and universality. The boron-doped diamond (BDD) with surface hydrogenation or oxygenation has matched energy levels corresponding to the target molecules and plays a critical role in achieving SERS. The enhancement factor based on BDD substrates can reach 104-105, which approaches those obtained with most nanostructured compound semiconductors and is nearly 3-4 orders of magnitude higher than those of state-of-the-art single-element semiconductors (silicon, germanium, and graphene). The mechanism of SERS is determined to be charge transfer with vibronic coupling, which could enhance the molecular polarizability tensor. Because of its unique properties such as chemical inertness, wide bandgap, modulated doping, surface functionalization, biocompatibility, and high thermal conductivity, the single-element semiconductor diamond can serve a high-performance semiconductor SERS platform with applications in broad fields.

Atomic Force Microscopic and Raman Investigation of Boron-Doped Diamond Nanowire Electrodes and Their Activity toward Oxygen Reduction

Reactive ion etching of diamond interfaces using oxygen plasma is a widely used approach for the formation of diamond nanowires. In this paper, we highlight the influence of the doping level of the etched diamond substrate on the density of the resulting nanowires. Heavily boron-doped diamond interfaces result in very dense diamond nanowires, while etching of low boron-doped diamond substrates results in sparsely formed nanostructures, as boron dopant atoms in the diamond act as masks during the etching process. In pursuit of a better understanding of doping and plasma etching effects, we demonstrated by performing Raman imaging on single diamond nanowires that the etching process leads to a dedoping of the wire tip and a partial transformation of diamond to sp2 carbon. The etching process does not, however, alter the initial diamond feature of the rest of the nanowire. Finally, the activity of the different diamond nanowires toward oxygen reduction in alkaline solution was investigated. Interestingly, hi...

Large-scale, all polycrystalline diamond structures transferred onto flexible Parylene-C films for neurotransmitter sensing.

Boron-doped diamond (BDD) has superior electrochemical properties for bioelectronic systems. However, due to its high synthesis temperature, traditional microfabrication methods have limits to integrating BDD with emerging classes of flexible, polymer-based bioelectronic systems. This paper introduces a novel fabrication solution to this challenge, which features (i) a wafer-scale substrate transfer process with all diamond structures transferred onto a flexible Parylene-C substrate and (ii) Parylene anchors introduced to strengthen the bonding between BDD and Parylene substrates, as demonstrated by a peeling test. The electrochemical properties of the transferred BDD-polymer electrodes are evaluated using (i) an outer sphere redox couple Ru(NH3)62+/3+ to study the electron transfer process and (ii) quantitative and qualitative studies of the neurotransmitter redox couple dopamine/dopamine-o-quinone. A linear response of the BDD sensor to dopamine concentrations of 0.5 μM to 100 μM is observed (R2 = 0.999) with a sensitivity of 0.21 μA cm-2 μM-1. These examples of fabricated diamond-polymer devices suggest a broad application in advanced bioelectronics and optoelectronics.

Modification with mesoporous platinum and poly(pyrrole-3-carboxylic acid)-based copolymer on boron-doped diamond for nonenzymatic sensing of hydrogen peroxide

A sensitive, accurate, free of oxygen interference electrochemical sensing approach was developed in this study for H2O2 level, an important parameter in clinical, biological and environmental fields. A boron-doped diamond (BDD) electrode was modified with mesoporous platinum (MPrPt) by electrodeposition of Pt–Cu alloy and anodic dissolution of Cu from the alloy, followed by the electropolymerization of a poly(pyrrole-3-carboxylic acid) (PPy3C) and polypyrrole (PPy) (PPy3C: PPy=4:1, molar ratio) copolymer. SEM micrographs revealed that MPrPt irregularly spreads on the BDD surface as ~100nm mesoporous and snow-flake-like nanoclusters, with a pore size of 10~15nm, and a trace amount of remnant Cu. The resulting Pt roughness factor and the effective surface area of the MPrPt/BDD were significantly larger, and its charge-transfer resistance was much smaller than those of the Pt nanoparticle modified BDD electrode. The PPy3C–PPy/MPrPt/BDD electrode exhibited very much sensitive, selective, precise, accurate, stable, reproducible, and a wide linear range of H2O2 responses at neutral pH under ambient condition, with similar sensitivity and S/N ratio to those under nitrogen protection. The limit of detection (LOD) for H2O2 was 2μM, with linearity range of 5μM~49mM (4 orders of magnitude). The BDD substrate, MPrPt, and the PPy3C–PPy copolymer together exerted a synergic effect to the prominent sensing performance. The detection was free from endogenous oxygen interference, one of the most critical issues in microanalysis, in vivo monitoring and field applications.

(Invited) Surface Passivation of High-k Dielectric Materials on Diamond Thin Films

Single-crystalline CVD diamond films have excellent electrical and material properties with potential in high power, high voltage and high frequency applications that are out of reach for conventional semiconductor materials. For realization of efficient devices (e.g. MOSFET), finding a suitable dielectric is essential to improve the reliability and electrical performance of devices. In the current study, we present results from surface passivation studies by high-k dielectric materials such as aluminum oxide and hafnium oxide deposited by ALD on intrinsic and boron doped diamond substrates. The hole transport properties in the intrinsic diamond films were evaluated and compared to unpassivated films using the lateral time-of-flight technique. The MOS capacitor structure, which forms the basic building block of the MOSFET, is discussed.

(Invited) Surface Passivation of High-k Dielectric Materials on Diamond Thin Films

Single-crystalline CVD diamond films have excellent electrical and material properties with potential applications in high power, high voltage and high frequency applications that are out of reach for conventional semiconductor materials. For realization of efficient devices (e.g. MOSFET), finding a suitable dielectric is essential to improve the reliability and electrical performance of devices. In the current study, we present results from surface passivation studies by high-k dielectric materials such as aluminum oxide and hafnium oxide deposited by ALD on intrinsic and boron doped diamond substrates. The hole transport properties in the intrinsic diamond films were evaluated and compared to unpassivated films using the lateral time-of-flight technique. Also, for the advancement of diamond-based electronic devices, the fabrication of MOSFET is crucial as this device finds applications in numerous fields of power electronics and high frequency systems. The MOS capacitor structure which forms the basic building block of the MOSFET is discussed. Inversion phenomenon crucial for the operation of MOSFET observed for the first time in boron doped diamond will be discussed.

ZnO Electrodeposition on Boron-Doped Diamond: Effects of Zinc Precursor Concentration

ZnO is a wide band gap (3.32 eV) semiconductor with n-type conductivity, which is used in many devices for different applications, including gas sensors, transparent electrodes, and acousto- and electro-optical devices. Recently, the combination of ZnO with boron-doped-diamond (BDD) was used in order to make heterojunctions [1], surface acoustic-wave (SAW) devices [2] and biosensors electrodes [3]. On the majority of presents works, ZnO was deposited on BDD by chemical vapor deposition (CVD) [4], magnetron sputtering [5] or atomic layer deposition (ALD) [6]. The electrodeposition represents an interesting new way for the deposition of ZnO on BDD. The electrodeposition of ZnO has been successfully performed on many conductive substrates [7] but only one time on BDD [8]. This chemical route presents a few advantages such as low cost and possibility to obtain a large range of structures from the dense layer up to well-defined nanostructures. The electrodeposition of a metal oxide such as ZnO consists to a redox process at the electrode surface, to raise the local pH and then to precipitate an oxide or hydroxide phase. Three different precursors can be used to produce hydroxide at electrode surface: hydrogen peroxide, nitrite salt or dissolved oxygen. This last one is used in our work. Dissolved oxygen is reduced, raising the local pH on the conductive diamond electrode and causing the precipitation of zinc hydroxide [9]. Then the dehydration of hydroxide leads to zinc oxide according to the following scheme. O2 + 2 H2O + 4 e- -> 4 OH- (1) Zn2+ + 2 OH- -> Zn(OH)2 (2) Zn(OH)2 -> ZnO + H2O (3) In this work, zinc chloride (ZnCl2) as precursor is used for the first time on BDD and potassium chloride (KCl) as support electrolyte. Our aim was to study the influence of deposition parameters such as zinc precursor concentration, substrate’s surface chemistry or bath temperature, on ZnO morphologies. The resulting ZnO deposits were characterized using X-ray Diffraction (XRD) and scanning electron microscope (SEM). The effect of [Zn2+] is illustrated on figures 1 and 2. As evidencing by XRD (Fig. 1), deposits obtained at 60°C, on as-grown BDD substrate, with 1 mM and 5 mM of Zn2+ correspond to well-crystallized zinc oxide. In both cases, the intensity of diffraction peak (002) indicates a preferential growth to the c-axis. The diffraction peaks from the substrate are labeled with an asterisk. SEM images (fig. 2) confirm the preferential orientation along c-axis. However, ZnO morphologies are completely different by changing Zn2+ concentration. Indeed, with a concentration of 5 mM, micrometric hexagonal grains are obtained while with a concentration ≤1 mM, nanometric pyramids are grown. Finally, our work shows that electrodeposition of ZnO is fully applicable on diamond substrate. And, parameters such as concentration of Zn2+, BDD’s surface chemistry or bath temperature, allow modifying the morphology of deposits.

Inversion in Metal–Oxide–Semiconductor Capacitors on Boron-Doped Diamond

For the advancement of diamond-based electronic devices, the fabrication of metal-oxide-semiconductor field-effect transistors (MOSFETs) is crucial, as this device finds applications in numerous fields of power electronics and high-frequency systems. The MOS capacitor forms the basic building block of the MOSFET. In this letter, we describe planar MOS capacitor structures fabricated with atomic layer deposited aluminum oxide as the dielectric on oxygen-terminated boron-doped diamond substrates with different doping levels. Using capacitance-voltage measurements, we have, for the first time, observed inversion behavior in MOS structures on boron-doped diamond, with a doping concentration of 4.1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">19</sup> /cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> .

Synthesis and Electrocatalytic Performance of BDD-Supported Platinum Nanoparticles

Platinum nanoparticles were deposited on boron-doped diamond substrate by electroless method without pre-activation. The mechanism of this deposition is a galvanic process along with a chemical process. Platinum particles are in nanoscale with diameter around 30-50 nm and height of around 3 nm observed from AFM and SEM images. The electrochemical activity of Pt nanoparticles was evaluated by cyclic voltammograms of hydrogen desorption process in 0.5 M H2SO4. The deposited platinum shows great stability in subsequent cycling in sulfuric acid and exhibits a high selectivity toward H2O2 detection in the range of 1 to 400 μM compared with those produced by electrochemical deposition.