Films Of Pt Research Articles

Anodic electrocatalytic conversion of carboxylic acids on thin films of RuO2, IrO2, and Pt

The electrocatalytic upgrading of carboxylic acids, abundant biomass-derived molecules, remains a challenging task. Herein, we report an electrocatalytic decarboxylation (ECDX) approach for the conversion of carboxylic acids into paraffins, olefins, and alcohols via (non-)Kolbe electrolysis on thin films (TFs). The ECDX rate, product selectivity, and current efficiency were potential and electrode dependent. For example, the ECDX activity of RuO2-TF was similar to that of Pt foil, but the selectivity to Kolbe products was lower on the former. RuO2-TF showed about five times higher rates for the oxygen evolution reaction than Pt foil, which resulted in lower current efficiency. The ECDX and O2 evolution activities of IrO2-TF were potential dependent, but this electrode was selective to non-Kolbe products with low current efficiency (<10 %). This work highlights the performance of thin films as an alternative to bulk metals as anodes for oxidative upgrading of carboxylic acids.

Low-temperature formation of platinum silicides on polycrystalline silicon

Phase formation and transitions in platinum silicide films on polycrystalline Si in the process of Pt magnetron sputtering and heat treatments at different temperatures are studied using X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and X-ray diffractometry. Phases of amorphous and polycrystalline Pt$_3$Si and Pt$_2$Si are shown to form during the room-temperature Pt deposition on poly-Si beneath the Pt layer. The relaxation of the interfacial film and partial transformation of Pt$_3$Si into Pt$_2$Si occurs as a result of the thermal treatment for 30 minutes in the temperature range from 125 to 300$^{\circ}$C. The Pt$_3$Si and Pt$_2$Si phases crystallize to PtSi due to annealing at the temperatures from 320 to 480$^{\circ}$C for the same time period.

Analysis on Sensitivity of Semiconductor Methane Gas Sensors by Ultrasonic Process

The thin films of Pt and Zn were coated with on the electrode in the board. Thin films of Pt are fabricated by ion plasma and Zn is manufactured by DC sputtering methods. Then the deposited boards were produced by ultrasonic chemical deposition in 0.01 M aqueous solution of C6H12N4 and Zn(NO3)2∙6H2O. To make the ZnO prepared-substrates were heat-treated at 600 °C for 1 hour and the sensitivity of ZnO-structured sensors was tested for Methane gas. In the experiment, the concentrations of Methane gas ranged from 15% to 40% LEL. We measured the change of the voltage before and after the Methane gas injections to judge whether it had a suitable performance as the Methane gas sensors. As a result of the sensitivity of the fabricated sensor, it was found that the voltage increases according to the Methane concentration. The sensitivity of the sensor constantly increased, so the graph showed a linear shape. Also, the fabricated sensors showed very short stabilization time, fast reaction and recovery. As a result, the using possibility of the detector is suggested where detection is required.

Electrochemical Atomic Layer Deposition: Self-Terminated Electrodeposition Reactions

Recently, an inexpensive “wet form” of ALD based on self-terminated electrodeposition reactions was uncovered that enables controlled formation of ultrathin films of Pt, Ir and iron group metals and alloys thereof. Common to all these systems is the role of reaction intermediates, namely adsorbed H or OH-, in the quenching of metal deposition reactions. Further details on the mechanisms of self-terminated deposition reactions will be discussed. Likewise, the utility and relevance of the process to the synthesis of nanoparticles and thin films, and the study of bimetallic electrocatalysts will be detailed.

Fabrication of platinum thin films for ultra-high electrocatalytic hydrogen evolution reaction

While the noble metals (e.g., platinum, (Pt)) remain the benchmark electrocatalyst for the hydrogen evolution reaction (HER), their mass production require a reduced metal loading and faster fabrication protocols. The aim of the present work is to prepare Pt thin films by simple and fast fabrication technique, and to evaluate their performance for HER. The thin films of Pt are grown on two substrates, namely titanium foil (Ti) and nickel foam (NF), using a single step aerosol assisted chemical vapor deposition (AACVD) method. The film deposition time are varied from 20 to 60 min. Microscopic analyses suggest a gradual evolution of the films into percolated and/or porous nanostructures, a feature that remains highly desired to allow the maximum access of active sites. The performance of the as-prepared electrodes is evaluated by monitoring the HER in acidic electrolyte. The Pt film on nickel foam (Pt/NF) exhibits better electrical conductivity and smaller charge transfer resistance, while the film deposited on the Ti foil (Pt/Ti) demonstrates superior catalytic activity per active sites. The as-prepared Pt/Ti and Pt/NF electrodes produce 10 mA cm−2 at overpotential of 28 mV and 26 mV, respectively, better in performance than commercial Pt/C electrode (~39 mV), set a new bench mark electrocatalyst for the HER.

Versatile Pt(II) Pyrazolate Complexes: Emission Tuning via Interplay of Chelate Designs and Stacking Assemblies.

Three homoleptic Pt(II) metal complexes [Pt(imPz)2] (1), [Pt(imiz)2] (2), and [Pt(imMz)2] (3) were synthesized from the treatment of Pt(DMSO)2Cl2 and functional imidazolyl pyrazole in refluxing tetrahydrofuran (THF). Alternatively, the heteroleptic Pt(II) complexes [Pt(imPz)(fppz)] (4), [Pt(imiz)(fppz)] (5), and [Pt(imMz)(fppz)] (6) were obtained from the treatment of a common intermediate [Pt(fppzH)Cl2] with a corresponding imidazolyl chelate. Pt(II) complexes 1, 2, and 5 were studied by single-crystal X-ray diffraction to reveal the corresponding packing arrangement in their crystal lattices, among which both homoleptic complexes 1 and 2 formed monomeric species, while heteroleptic 5 aligned as a dimer with a nonbonding Pt···Pt contact of 3.574 Å. Subsequent photophysical examinations showed that the homoleptic 1-3 and heteroleptic 4-6 exhibited the structured sky-blue ππ* emission and structureless light-green-emitting metal-metal-to-ligand charge transfer (MMLCT) emission in the solid state, respectively. A shortened Pt···Pt interaction of approximately 0.34-0.35 nm was confirmed in thin films of all heteroleptic Pt(II) complexes 4-6 by grazing-incidence X-ray diffraction (GIXD) analyses. Finally, Pt(II) complex 6 was employed as a dopant in the fabrication of organic light-emitting diode (OLED) devices with varied doping ratios, among which OLEDs with only 1 wt % 6 in the SimCP host exhibited a maximum external quantum efficiency (EQE) of 5.8% and CIEx,y values of 0.20, 0.31. In contrast, OLEDs using a nondoped architecture (i.e., 100% of 6 in the emitting layer (EML)) achieved a maximum EQE of 26.8%, current efficiency (CE) of 91.7 cd A-1, and power efficiency (PE) of 80.1 lm·W-1 and CIEx,y values of 0.41, 0.55, manifesting their versatility in various degrees of stacking assemblies and hence facile color-tuning capability on OLEDs.

A setup for Seebeck coefficient measurement through controlled heat pulses.

A setup is designed for measuring the Seebeck coefficient (S) of materials in the form of thin films, bars, and wires. The main feature of this setup is its control in heating and cooling cycles. In this setup, a heat pulse is used to generate the temperature gradient. To demonstrate the capabilities of this setup, S versus T of standard wire samples such as Au-Fe (0.07%), chromel, Pt, and thin films of Pt and F doped SnO2 are presented. The standard uncertainty of the repeatability in the S measurement is found to be ∼±0.056 μV/K while the temperature stability is ∼±10 mK (at 320 K), estimated for a chromel wire sample. We have tested the setup in the temperature range 100 K-320 K, while it does not have any intrinsic limitations in going down to liquid He temperatures. For temperatures above 320 K, the limitation is due to gluing materials such as varnish.

Electrochemical Atomic Layer Deposition: Self-Terminated Electrodeposition Reactions

Recently, an inexpensive “wet form” of ALD based on self-terminated electrodeposition reactions was uncovered that enables controlled formation of ultrathin films of Pt, Ir and iron group metals and alloys thereof. Common to all these systems is the role of reaction intermediates, namely adsorbed H or OH-, in the quenching of metal deposition reactions. Further details on the mechanisms of self-terminated deposition reactions including its extension to substrates beyond Au and role in alloy co-deposition will be discussed. Likewise, the utility and relevance of the process to the synthesis of nanoparticles and thin films, and the study of bimetallic electrocatalysts will be detailed.

Rapid antibiotic susceptibility testing by resazurin using thin film platinum as a bio-electrode

Traditional antibiotic susceptibility testing methods take several days to confirm and start disease treatment. The lack of new antibiotics or drugs warrants a need for optimization of current diagnostic tools for immediate antibiotic susceptibility testing. We present a rapid screening method to evaluate the response of bacteria to antibiotics based upon the electrochemical measurement of live bacterial cell metabolic activity using an electroactive redox dye, resazurin. A thin film of Pt deposited over a glass substrate using the direct current sputtering technique was used as a working bio-electrode for electrochemical readouts. X-ray diffraction and scanning electron microscopy was carried out to characterize the Pt thin film. We tested the efficacy of the method using two different strains, Klebsiella pneumoniae (ATCC-700603) and Escherichia coli (ATCC-25922), against ampicillin, kanamycin and tetracycline. The dye, on incubation with viable bacteria, undergoes reduction and lowers the corresponding peak current value. However, in the presence of an effective antibacterial agent, reduction did not occur due to bacterial cell death and absence of a reducing environment. The electrochemical changes in peak current values were monitored using the differential pulse voltammetry technique and interpretation of the results obtained was based upon changes in peak current values. Our results depict a new methodology where a concentration of 104 cells/mL cells can be detected in less than 4 h. The results were also compared with the conventional disc diffusion method for susceptibility testing which has a bacterial incubation time of 18–24 h. The method can potentially be used for monitoring the susceptibility of bacterial strains towards existing antibacterial agents in an easy, rapid, reliable and inexpensive manner without any pre-cultivation of bacteria.

Solar Cells Constructed with Polythiophene Thin Films Grown along Tethered Thiophene-Dye Conjugates via Photoelectrochemical Polymerization.

A polythiophene-based solar cell (PTSC) is constructed by photoelectrochemically polymerizing thiophene onto an ultrathin compact TiO2 layer (150 nm thick) covered with a sub-monolayer of tethered 3-{5-[ N, N-bis(4-diphenylamino)phenyl]thieno[3,2- b]thiophen-2-yl}-2-cyano-acrylic acid dye (ca. 10% coverage). The influence of morphology and thickness of the PT film on the photocurrent generated by the PTSC was investigated. With a 270 nm thick PT film and 2,2',7,7'-tetrakis( N, N-di(4-methoxyphenyl)amino)-9,9'-spirobifluorene serving as the hole-transport material, the PTSC exhibited a short-circuit current density JSC of 12.90 ± 0.63 mA/cm2, an open-circuit voltage VOC of 0.81 ± 0.01 V, and a fill factor of 0.72 ± 0.01. The high conversion efficiency (7.52 ± 0.58%) of the PTSC is attributed to the controlled PT growth along the ordered and spatially accessible dye molecules at the compact TiO2 layer, which facilitates charge transfer, prevents the hole/electron recombination, and simplifies the polymer solar cell construction with a stable and easily processable material.

Flexible Energy Harvester Based on Poly(vinylidene fluoride) Composite Films.

In these days, we are facing emerging energy crisis due to depletion of fossil fuels. Therefore, renewable energy which is based on wind energy, mechanical force energy, microwave energy and vibrations energy have attracted a lot of attentions. Piezoelectric energy harvesting is one of the promising renewable energy sources. As the use portable electronic devices increases, the need for portable renewable energy sources further increases. Especially, piezoelectric materials can be the best selection due to their robust properties. In this research, piezoelectric composites were prepared and investigated for piezoelectric energy harvesting applications. In this study, two types of flexible energy harvesters, 0.36BS-0.64PT-PVDF composite and PVDF film, were prepared and analyzed. Due to its high Curie temperature and low lead content, BS-PT is expected to be a substitute for PZT in the near future. The composite materials based on the PVDF and 0.36BS-0.64PT film showed higher open circuit voltage (0.73 V) than PVDF film (0.49 V). Also, the stored voltage of 0.36BS-0.64PT-PVDF composite film was 330 nJ which is 5.68 times higher than 58 nJ for PVDF films. By introducing the piezoelectric BS-PT ceramics, 0.36BS-0.64PT-PVDF composite film shows the enhanced performance such as open circuit voltage, energy and dielectric constant compared with those of PVDF materials. It seems that 0.36BS-0.64PT-PVDF composite film is more suitable for flexible energy device.

FORMATION OF PLATINUM SILICIDE LAYERS DURING THE RAPID THERMAL PROCESSING OF THE SYSTEM PLATINUM-SILICON: STRUCTURAL-PHASE CHANGES

The paper presents the performed investigations of the structural-phase changes of the platinum-silicon system during rapid thermal processing (RTP) in the nitrogen medium within the temperature range from 200°C to 550°C with a step of 50 K and the time duration of 7 s. High effectiveness of the RTP process was demonstrated for formation of the thermally stable platinum silicides in the nanodimensional film (40 nm Pt)/(Si 111) substrate system. Within the temperature range of 200°C ≤ T ≤ 300°C during 7 s of the RTP process on the border of the → metallic film with the substrate there grows the Pt2Si layer at the expense of the Pt atoms diffusion into silicon through the layer of the growing silicide. It is peculiar for the temperature T = 300°C to use completely the film of Pt for 7 s in the process of the silicide formation of the single-phase system of Pt2Si. At 350°C ≤ T < 450°C formation is registered of the double-phase system of Pt2Si PtSi, starting from the interphase boundary of Si/Pt2Si predominantly at the expense of the oncoming diffusion of Si atoms into the layer of Pt2Si. The RTP temperature T = 450°C marks formation of the thermally stable structure of PtSi along the entire thickness of silicide, which is 50-100°C lower and substantially faster, than during the continuous furnace thermal treatment (FTT).

Hydrogen oxidation kinetics on platinum-palladium bimetallic thin films for solid acid fuel cells

Solid acid fuel cells (SAFCs) based on the proton-conductive electrolyte CsH2PO4 have shown promising power densities at an intermediate operating temperature of ∼250 °C. However, Pt loadings in SAFCs remain higher than desirable, and the electrocatalysis mechanisms in these devices are still unknown. Here, hydrogen oxidation kinetics on Pt and Pt-Pd bimetallic thin film electrodes on CsH2PO4 have been evaluated to establish the potential for a beneficial role of Pd in SAFC anodes. Symmetric cells fabricated by depositing a metal film on both sides of electrolyte discs are characterized for studying hydrogen electro-oxidation across the gas|metal|CsH2PO4 structure. It was found that Pd reacts with CsH2PO4, forming palladium phosphide at the metal-electrolyte interface. Accordingly, the activity of Pd was examined in a bilayer geometry of Pd|Pt|CsH2PO4|Pt|Pd. The bilayer Pt|Pd films showed much higher activity for hydrogen electro-oxidation than films of Pt alone, as measured by AC impedance spectroscopy. Ex situ low energy ion scattering and scanning transmission electron microscopy revealed that Pd diffused into the Pt layer under operating conditions. The dramatic impact of Pd along with its presence throughout the film suggests that it catalyzes reactions at both the metal-gas and metal-electrolyte interfaces, as well as increasing hydrogen diffusion rates through the films.

High Ferroelectricities and High Curie Temperature of BiInO3PbTiO3 Thin Films Deposited by RF Magnetron Sputtering Method☆☆Supported by the National Natural Science Foundation of China under Grant No 11304160, the Special Fund for Public Interest of China under Grant No 201510068, and the NUPTFC under Grant No NY215111.

Properties of ferroelectric xBiInO3-(1 − x)PbTiO3 (xBI-(1 − x)PT) thin films deposited on (101) SrRuO3/(200) Pt/(200) MgO substrates by rf magnetron sputtering method and effects of deposition conditions are investigated. The structures of the xBI-(1 − x)PT films are characterized by x-ray diffraction and scanning electron microscopy. The results indicate that the thin films are grown with mainly (001) orientation. The chemical compositions of the films are analyzed by scanning electron probe and the results indicate that the loss phenomena of Pb and Bi elements depend on the pressure and temperature during the sputtering process. The sputtering parameters including target composition, substrate temperature, and gas pressure are adjusted to obtain optimum sputtering conditions. To decrease leakage currents, 2 mol% La2O3 is doped in the targets. The P–E hysteresis loops show that the optimized xBI-(1 − x)PT (x = 0.24) film has high ferroelectricities with remnant polarization and coercive electric field . The Curie temperature is about 640 °C. The results show that the films have optimum performance and will have wide applications.

Photodeposition of metals from inks and their application in photocatalysis

Films of Ag, Pt and Au nanoparticles are photodeposited onto a range of commercial TiO2 based photocatalytic materials, such as paint, tile, awning fabric and glass, as well as a TiO2 sol-gel film, using an aqueous ink containing a sacrificial electron donor, glycerol, and the appropriate metal salt. The photodeposited metal films appear to be comprised of a fine covering of nanoparticular metal islands distributed evenly across the surface of the TiO2 sol-gel film, with some large aggregated particles for Pt (106 nm) and Au (33 nm). The rate of deposition of Ag is particularly fast, since a 10 s exposure to 2 mW cm−2 UVA light produces a very noticeable colour change, which is ca. 60 times that of the other two metal-ion containing inks. When combined with a photomask, the metal inks are used to create finely detailed metal film images on the surfaces of a wide variety of different, mainly commercial, photocatalytic materials; a fine metal mesh photomask is used to make metal micro-patterns. When used to promote the photocatalysed oxidation of organic pollutants dissolved in aqueous solution, such as 4CP and MB, the enhancement in photocatalytic activity (compared to a plain TiO2 film) exhibited by a photodeposited Pt on TiO2 film is modest (16–35%), however, the enhancement is marked (234%) for the photocatalysed oxidation of CO to CO2. In contrast, the Au and Ag films appear to depress the inherent activity of the naked TiO2. The Pt/TiO2 film also enhances significantly the photocatalysed oxidation of a film of soot (179%) but not of stearic acid (−23%); the Ag and Au films appear to impede the former reaction. The Pt/TiO2 film exhibits the most significant enhancement in rate for the photocatalysed reduction of water to H2 by ethanol, i.e. 62 times that of the Ag/TiO2 film, which exhibits only a modest activity, which in turn is better than a naked TiO2 film which shows no activity. The potential of the metal (ion) inks to more easily make photodeposited metal films on semiconductor photocatalyst films is discussed briefly.

Effects of annealing process and the additive on the electrical properties of chemical solution deposition derived 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 thin films

0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (PMN–PT) thin films were deposited on (111)Pt/Ti/SiO2/Si substrates via the chemical solution deposition. Both of the annealing process and additive methanamide play an obvious part in the structure and electrical properties of PMN–PT films. The optimized high-qualitied PMN–PT thin film in present work is fabricated with the methanamide in the precursor and annealed at 650 °C for 20 min. The film exhibits pure perovskite phase and superior ferroelectricity. The saturation polarization Ps and remanent polarization Pr are 52.1 µC/cm2 and 18.7 µC/cm2 at 500 kV/cm with 1000 Hz. It also shows low leakage current density of approximately 1.0 × 10− 8 A/cm2 at 200 kV/cm.

(Invited) Self-Terminated Electrodeposition Reactions

Recently, an inexpensive “wet form” of ALD based on self-terminated electrodeposition reactions was uncovered that enables controlled formation of ultrathin films of Pt, Ir and iron group metals and alloys thereof. Common to all these systems is the role of reaction intermediates, namely adsorbed H or OH-, in the quenching of metal deposition reactions. Further details on the mechanisms of self-terminated deposition reactions will be discussed. Likewise, the utility and relevance of the process to the synthesis of nanoparticles and thin films, and the study of bimetallic electrocatalysts will be detailed.

(Invited) Growth and Catalytic Performance of Pd and Pd-Pt Alloy Ultrathin Films on Au By Surface Limited Redox Replacement of H UPD Layers in One-Cell Configuration

In the ongoing effort of solving the energy problem of humanity the design, fabrication and testing of catalysts has been playing a central role for the last couple of decades. Besides the known application of Pd hydrogen gas storage a growing interest has been seen in the use of this metal and its alloys in catalytic reactions with relevance to fuel cells. While Pt is still considered best catalyst for fuel cell applications its high cost and limited supply calls more and more for intensifying the effort of replacing Pt with Pd. Means of growing Pd on conductive materials include a variety of expensive vacuum deposition approaches that need sophisticated equipment and high temperature. An alternative to those is electrodeposition that besides the standard bulk deposition, offers a variety of ultra-thin film growth approaches that could facilitate the deposition of uniform and flat continuous Pd films on polycrystalline Au. Among those, the electrochemical atomic layer deposition of Pd under optimum conditions was first developed for automated flow cell. Our group has been working recently on developing fine-tuned approaches for the growth of epitaxial Pd on Au using always readily available one-cell configuration instead, of sophisticated automated flow cells. The growth uses surface limited redox replacement (SLRR) reaction of underpotentially deposited (UPD) Cu or H sacrificial layers. After a set of iteratively applied deposition cycles, the as-deposited Pd or Pt-Pd films are tested for surface roughness using characteristic HUPD and CuUPD cyclic voltammetry (CV) curves and the efficiency of the deposition technique is measured by stripping charge determination. Also, XPS characterization was used for determining both, the alloy composition in the case of Pt-Pd deposition and the presence / absence of impurities incorporating in the deposit in the case of pure Pd growth. The quasi-2D growth resulting in smooth and uniform Pd-film morphology has also been confirmed up to 20 SLRR cycles by in-situ STM. Consequently, the accordingly deposited films at minimum thickness are tested for catalytic activity and durability in formic acid oxidation reactions. In this presentation results of this work will be presented in detail and critically discussed. The emphasis is on the illustration of deposition approach that has been developed to take place in one cell and in the specifically in the case of SLRR of HUPD results in a theoretically contamination free deposits. It is also demonstrated that this approach provides for maximum deposition efficiency engaging also adsorbed H in the replacement scenario. The CV results indicate the deposition of smooth Pd films taking place for up to 30 SLRR cycles for HUPD and CuUPD sacrificial layers, respectively. This is followed by a rapid transition to dendritic growth at higher thickness. The underlying kinetic reasons for such abrupt transition are also considered and critically discussed. Finally, the applicability of the proposed facile SLRR approach has been demonstrated through testing for catalytic activity and durability in formic acid oxidation of ultrathin films of Pd, Pt and Pt-Pd alloys with different composition. The critical analysis of the testing outcome suggested that a 1:2 Pt-Pd alloy exhibits activity and durability that are comparable with those of pure Pt and substantially better to those of pure Pd.

Thickness and temperature dependences of dielectric properties of {111}-oriented epitaxial Pb(Mg1/3Nb2/3)O3 and 0.6Pb(Mg1/3Nb2/3)O3–0.4PbTiO3 films

The effects of film thickness and composition on crystal structure and dielectric properties were investigated for {111}-oriented epitaxial Pb(Mg1/3Nb2/3)O3 (PMN) and 0.6Pb(Mg1/3Nb2/3)O3–0.4PbTiO3 (0.6PMN–0.4PT) films of various thicknesses grown on (111)cSrRuO3//(111)SrTiO3 substrates by pulsed metal organic chemical vapor deposition (MOCVD). When the film thickness of {111}-oriented PMN films increased from 500 to 1300 nm, the relative dielectric constant at room temperature increased from 1600 to 2800 at 10 kHz. This tendency was similar to our previous result for {100}-oriented PMN films. On the other hand, the relative dielectric constant at room temperature slightly increased from 2500 to 2700 at 10 kHz with the increase in film thickness from 750 to 2500 nm in the case of {111}-oriented 0.6PMN–0.4PT films. PMN films show strong frequency dependences of maximum relative dielectric constant against temperature, εr(max), and the temperature of εr(max), T(max), together with a strong thickness dependence. On the other hand, 0.6PMN–0.4PT films show small frequency dependences of εr(max) and T(max) together with a small film thickness dependence. These results show a strong film composition dependence of the dielectric properties of the films in a PMN–PT system such as frequency and thickness.

Barrier heights of Au, Pt, Pd, Ir, Cu on nitrogen terminated (1 0 0) diamond determined by X-ray photoelectron spectroscopy

In this work, we used X-ray photoelectron spectroscopy to measure barrier height values for different metals (Au, Pt, Pd, Ir, Cu) on nitrogen terminated (1 0 0) diamond. Three types of diamond surface (hydrogen-, oxygen-, fluorine-terminated diamond surface) were used as the initial surfaces. Then, nitrogen terminated diamond surface was formed by reactive ion etching on the initial diamond surfaces for comparison. Thin films of Au, Pt, Pd, Ir and Cu were evaporated by electron beam to form metal/N-diamond contacts, respectively. The barrier height values for Au, Pt, Pd, Ir and Cu on nitrogen terminated (1 0 0) diamond contacts were determined to be 2.37 eV, 2.14 eV, 1.78 eV, 2.20 eV and 1.84 eV, respectively.