Homogeneous Diamond Research Articles

Superior mechanical properties of an additively manufactured gradient lattice structure through FEM simulation and in-situ compression tests

Currently, the increasing incidence of bone defects and damage due to diseases and trauma, the treatment of bone defects usually uses autologous bone graft or allogeneic bone graft, however, the amount of autologous bone is limited, and there is also the risk of infection at the site of bone extraction, and allogeneic bone graft also faces problems such as disease transmission and immune rejection. In summary, artificial bone provides a new option for patients. This study investigates the mechanical properties of homogeneous and gradient Gyroid and Diamond porous structures, designed with average porosities of 50%, 60%, and 70%, using triply-periodic minimal surface models for artificial joints. Finite Element Method simulations and compression tests were employed to characterize the mechanical properties of Ti6Al4V porous scaffolds fabricated using the selective laser melting technique. The measured elastic modulus of the scaffolds ranged from 6.24 to 10.5GPa, meeting the requirements for orthopedic implants. Gyroid structures were shown to exhibit superior nominal stiffness compared to Diamond structures at equivalent porosity levels. Furthermore, the linear gradient porous structures demonstrated significantly higher elastic modulus, yield strength, and compressive strength compared to homogeneous porous structures, with increases of 66.9%, 20.3%, and 16.5%, respectively. The energy absorption capacity of the linear gradient porous structure was also found to be 3.3-fold greater than that of the homogeneous structure.The lightweight design of this linear gradient porous structure provides the basis for bone implants for biomedical applications.

Preparation, wear resistance, and impact toughness of homoepitaxial diamond film deposited on polycrystalline diamond compact by HFCVD method

To minimize the detrimental effects of cobalt binder on the thermal stability of polycrystalline diamond compact (PDC) under high temperature working conditions and enhance the PDC’s properties. Hot filament chemical vapor deposition diamond coated polycrystalline diamond compact (HFCVD-PDC) was prepared by depositing homogeneous epitaxial diamond film on the polycrystalline diamond layer (PCD layer) treated with cobalt binder removal. The effect of deposition pressure on the microstructure of the diamond film was investigated, and the PDC’s wear resistance was assessed using the abrasion ratio test. The drop hammer impact test was utilized to evaluate the impact toughness of the original PDC, cobalt removal PDC, and HFCVD-PDC. The results showed that a continuous and dense nanodiamond film with a cauliflower-like structure was formed on the PDC surface at the deposition pressure of 3 kPa. The abrasion ratio of the HFCVD-PDC increased by 67.44% compared to the original PDC, and by 33.29% compared to the cobalt removal PDC. Furthermore, filling nanodiamonds into the pores of cobalt removal PDC improved its impact toughness. These findings suggest that the application of homogeneous epitaxial diamond on the PCD layer can significantly improve the PDC’s wear resistance and impact toughness.

Global flattening realization and kinematic analysis of UV-assisted low-speed 3D dynamic friction-polished diamonds

Diamond has attracted extensive attention from many scholars because of its unique properties. However, there are still bottlenecks in how to achieve high efficiency polishing and global flattening of diamond which restrict its application. The aim of this study is to obtain a globally homogeneous flattened diamond surface in macro dimension by introducing a compound motion of the polished workpiece. It is shown that ultra-smooth diamond surface machining with global flattening can be realized by UV-assisted low-speed dynamic friction polishing technique, and the typical roughness is 0.175 nm as measured by 3D optical surface profiler. These experimental results demonstrate that the catalytic phase transition process of UV light is the underlying mechanism to realize the diamond surface polishing under low rotational speed conditions. Additionally, the composite motion of the diamond sample with the metal disk brings large enhancement to the effect of polishing global flattening on the sample surface. The theoretical and experimental studies in this paper provide novel ideas for achieving efficient and polished global flattening of diamond.

Impact of Methanol Concentration on Properties of Ultra-Nanocrystalline Diamond Films Grown by Hot-Filament Chemical Vapour Deposition

Diamond is a very interesting material with a wide range of properties, making it highly applicable, for example, in power electronics, chemo- and biosensors, tools’ coatings, and heaters. Due to the high demand for this innovative material based on the properties it is already expected to have, it is important to obtain homogeneous diamond layers for specific applications. Doping is often chosen to modify the properties of layers. However, there is an alternative way to achieve this goal and it is shown in this publication. The presented research results reveal that the change in methanol content during the Hot Filament Chemical Vapour Deposition (HF CVD) process is a sufficient factor to tune the properties of deposited layers. This was confirmed by analysing the properties of the obtained layers, which were determined using Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and an atomic force microscope (AFM), and the results were correlated with those of X-ray photoelectron spectroscopy (XPS). The results showed that the increasing of the concentration of methanol resulted in a slight decrease in the sp3 phase content. At the same time, the concentration of the -H, -OH, and =O groups increased with the increasing of the methanol concentration. This affirmed that by changing the content of methanol, it is possible to obtain layers with different properties.

Micro and Nano-Crystalline Diamond Coatings of Co-cemented Tungsten Carbide Tools with Their Characterization

In this study, a bias-enhanced hot filament CVD system with methane and hydrogen as reactant gasses was used to deposit microcrystalline diamond (MCD) and nanocrystalline diamond (NCD) films on Co-cemented tungsten carbide substrates. They were then characterized using FE-SEM, Optical microscopy, XRD, and Raman Spectroscopy. Nanocrystalline diamond coating displays wide carbon peaks near 1350 cm−1 and 1580 cm−1 in Raman Spectroscopy, which correspond to D band and G band of carbon, and a sharp band increase near 1140 cm−1 because of the presence of trans-polyacetylene, confirming the sample as a nanocrystalline diamond. Similarly, the microcrystalline diamond phase was observed at 1350 cm−1 as broadened carbon peaks. The average grain size of the homogenous diamond film was roughly less than 90 nm, several tens of nanometres. The average indentation depths were 45 nm and 63 nm of MCD and NCD coatings and their average hardness values were found 80GPa and 50GPa, respectively. The morphology of the samples was observed using AFM, the average root mean square roughness of the MCD sample in the scanned area was found to be 354.11 nm and of the NCD sample was found to be 142.71 nm this indicates that the nanocrystalline diamond-coated WC was much smoother and had a smaller grain size than microcrystalline diamond coated ones. The values of the coefficient of friction vary from 0.38 to 0.42 for MCD coated sample. In contrast, for the NCD samples, the variations in the coefficient of friction were 0.30–0.36. A low coefficient of friction was observed in NCD as compared to MCD due to the presence of the graphite carbon phase.

Effect of hydrogen protection on synthetic polycrystalline diamond composite

This article discusses the effects of hydrogenation pretreatment on synthetic polycrystalline diamond composite(PDC). Hydrogen is used for hydrotreating cobalt metal catalyst as a role to protective cobalt and improve the catalytic activity of cobalt in the synthesis of PDC. The PDC is synthesized in a hinged Hexa-orientation Press. The catalytic mechanism of hydrogenation in synthesis PDC is discussed. The polycrystalline diamond (PCD) phases in the PDC samples are confirmed by X-ray diffraction method (XRD). Scanning electron microscopy (SEM) images reveal the PCD layer surface consist of a homogeneous diamond, cobalt and tungsten carbide alloy. Raman and abrasion ratio methods are used to analyze the performance of PDC. Experimental results show that the residual stress of PCD layer surface is tensile stress and the new method with hydrogenation can improve the abrasion ratio of PDC.

Effect of the anisotropy of etching surface morphology on light-trapping and photovoltaic conversion efficiencies of silicon solar cell

A homogeneous diamond wire sawing multicrystalline Si surface with nanoscale oval pits was obtained in an acid solution by adding NaNO2, polyethylene glycol–polyvinyl alcohol, and dodecylbenzene sulfonic acid at 12 °C for 130 s. The textured surface showed orientation dependence. The anisotropy of H/D caused different experimental results. The Rave of incident light originating from the direction parallel to saw marks was 22–27% larger than that from the direction perpendicular to saw marks. The photovoltaic conversion efficiency was 0.6–0.8% higher when the thin grid line of Ag electrode was parallel to the saw marks than when in the perpendicular direction. These results indicated that using saw marks can improve the conversion efficiency of solar cells.

The Non-Eigenvalue Form of Liouville’s Formula and α-Matrix Exponential Solutions for Combined Matrix Dynamic Equations on Time Scales

In this paper, the non-eigenvalue forms of Liouville’s formulas for delta, nabla and α -diamond matrix dynamic equations on time scales are given and proved. Meanwhile, a diamond matrix exponential function (or α -matrix exponential function) is introduced and some classes of homogenous linear diamond- α dynamic equations which possess the α -matrix exponential solutions is studied. The difference and relation of non-eigenvalue forms of Liouville’s formulas among these representative types of dynamic equations is investigated. Moreover, we establish some sufficient conditions to guarantee transformational relation of Liouville’s formulas and exponential solutions among these types of matrix dynamic equations. In addition, we provide several examples on various time scales to illustrate the effectiveness of our result.

Fundamental limits for near-junction conduction cooling of high power GaN-on-diamond devices

The integration of differing materials can enable breakthrough performance for semiconductor devices. One example is the integration of gallium nitride (GaN) and diamond to form GaN-on-diamond, which enables high-power GaN devices to achieve extreme power densities and, arguably, approaches fundamental limits for conduction cooling. Here, we examine the fundamental limits for near-junction phonon conduction cooling of GaN-on-diamond devices via finite element calculations of their lowest possible thermal resistance. A semi-classical transport theory for phonons interacting with interfaces and defects is used to calculate the in-plane thermal conductivity of a GaN epilayer and thereby accurately account for the thermal spreading resistance of the GaN layer. The device thermal resistance of a state-of-the-art GaN-on-diamond structure is predicted to be ∼13.0 K mm W−1 for a 12 finger device with 30 μm gate-to-gate spacing and a power dissipation of 5 W mm−1. For the same multifinger cell geometry and dissipated power, device thermal resistances as low as ∼10.0 K mm W−1 may be possible with assuming anisotropic but homogeneous diamond, as well as the absence of phonon scattering by external defects in the GaN layer and interface.

Continuous functionally graded porous titanium scaffolds manufactured by selective laser melting for bone implants.

A significant requirement for a bone implant is to replicate the functional gradient across the bone to mimic the localization change in stiffness. In this work, continuous functionally graded porous scaffolds (FGPSs) based on the Schwartz diamond unit cell with a wide range of graded volume fraction were manufactured by selective laser melting (SLM). The micro-topology, strut dimension characterization and effect of graded volume fraction on the mechanical properties of SLM-processed FGPSs were systematically investigated. The micro-topology observations indicate that diamond FGPSs with a wide range of graded volume fraction from 7.97% to 19.99% were fabricated without any defects, showing a good geometric reproduction of the original designs. The dimensional characterization demonstrates the capability of SLM in manufacturing titanium diamond FGPSs with the strut size of 483-905µm. The elastic modulus and yield strength of the titanium diamond FGPSs can be tailored in the range of 0.28-0.59GPa and 3.79-17.75MPa respectively by adjusting the graded volume fraction, which are comparable to those of the cancellous bone. The mathematical relationship between the graded porosity and compression properties of a FGPS was revealed. Furthermore, two equations based on the Gibson and Ashby model have been established to predict the modulus and yield strength of SLM-processed diamond FGPSs. Compared to homogeneous diamond porous scaffolds, FGPSs provide a wide range of mutative pore size and porosity, which are potential to be tailored to optimize the pore space for bone tissue growth. The findings provide a basis of new methodologies to design and manufacture superior graded scaffolds for bone implant applications.

Influence of the surface microstructure on the adhesion of a CVD-diamond coating on steel with a CrN interlayer

forming tool coating. Most of the forming tools are made of steel, so that especially the coatability of steel by a polycrystalline diamond coating would rise the range of fields of application. The polycrystalline CVD-diamond coatings are deposited by a laser induced plasma CVD process, without a vacuum chamber. Various surface microstructures were investigated regarding their influence on the residual stresses to prevent a flaking of the coating: on the one hand, deterministic structures generated by ultrasonic vibration assisted milling (UVAM) and on the other hand, stochastic structures manufactured by blasting and polishing processes. For the UVAM, a surface prediction tool was used to design the surface microstructure beforehand. All steel substrates (material no. 1.2379) were coated in one batch by high-power impulse magnetron sputtering with a chromium nitride coating with a thickness of 2.4 μm. The specimens were analysed by laser microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and Raman spectroscopy. None of the microstructures investigated in this study was able to prevent delamination of the coating entirely. It could be shown that a roughness higher than Sa 0.1μm supports the interlocking between coating and surface as well as that sharp peaks inhibit a homogenous diamond coating deposition.

Micro-Structures of Nanodiamonds Grown on Silicon by Hot Filament Chemical Vapor Deposition

Abstract A method to grow homogeneous micro-sized diamond clusters on silicon by Hot-Filament Chemical Vapor Deposition in a homemade reactor is reported in this work. Thermal decomposition of a CH4:H2 mixture gases was carried out in a horizontal quartz-tube reactor at 2200 °C filament temperature and 1000 °C substrate temperature at relative low pressure around 150 Torr depositing diamonds on silicon wafers. The diamond micro-structures are formed by nano-crystalline diamonds, they have a rounded shape and a narrow particle size distribution around a micrometer. The diamond micro-structures synthesized in this work showed a strong Raman shift signal, a peak at 1330 cm‒1 typical of the diamond and a single optical trap was localized nearby 300 °C by Thermoluminescence analysis indicating that these diamond micro-structures could be a good thermoluminescent dosimeter material. Due to their excellent properties, diamonds obtained by this technique should find application in the biomedical and optoelectronic industry.

The effect of substrate holder size on the electric field and discharge plasma on diamond-film formation at high deposition rates during MPCVD

The effect of the substrate holder feature dimensions on plasma density (ne), power density (Qmw) and gas temperature (T) of a discharge marginal plasma (a plasma caused by marginal discharge) and homogeneous plasma were investigated for the microwave plasma chemical vapor deposition process. Our simulations show that decreasing the dimensions of the substrate holder in a radical direction and increasing its dimension in the direction of the axis helps to produce marginally inhomogeneous plasma. When the marginal discharge appears, the maximum plasma density and power density appear at the edge of the substrate. The gas temperature increases until a marginally inhomogeneous plasma develops. The marginally inhomogeneous plasma can be avoided using a movable substrate holder that can tune the plasma density, power density and gas temperature. It can also ensure that the power density and electron density are as high as possible with uniform distribution of plasma. Moreover, both inhomogeneous and homogeneous diamond films were prepared using a new substrate holder with a diameter of 30 mm. The observation of inhomogeneous diamond films indicates that the marginal discharge can limit the deposition rate in the central part of the diamond film. The successfully produced homogeneous diamond films show that by using a substrate holder it is possible to deposit diamond film at 7.2 μm h–1 at 2.5 kW microwave power.

Diamond/β-SiC film as adhesion-enhanced interlayer for top diamond coatings on cemented tungsten carbide substrate

In present work, diamond/β-SiC composite interlayers were deposited on cemented tungsten carbide (WC-6%Co) substrates by microwave plasma enhanced chemical vapor deposition (MPCVD) using H2, CH4 and tetramethylsilane (TMS) gas mixtures. The microstructure, chemical bonding, element distribution and crystalline quality of the composite interlayers were systematically characterized by means of field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), electron probe microanalysis (EPMA), Raman spectroscopy and transmission electron microscropy (TEM). The influences of varying TMS flow rates on the diamond/β-SiC composite interlayers were investigated. Through changing the TMS flow rates in the reaction gas, the volume fraction of β-SiC in the composite interlayers were tunable in the range of 12.0%–68.1%. XPS and EPMA analysis reveal that the composite interlayers are composed of C, Si element with little cobalt distribution. The better crystallinity of the diamond in the composite is characterized based on the Raman spectroscopy, which are helpful to deposit top diamond coatings with high quality. Then, the adhesion of top diamond coatings were estimated using Rockwell C indentation analysis, revealing that the adhesion of top diamond coatings on the WC-6%Co substrates can be improved by the interlayers with the diamond/β-SiC composite structures. Comprehensive TEM interfacial analysis exhibits that the cobalt diffusion is weak from WC-6%Co substrate to the composite interlayer. The homogeneous microcrystalline diamond coatings with the most excellent adhesion can be fabricated on the substrates with the composite interlayer with the β-SiC/diamond ratio of about 45%. The composite structures are appropriate for the application in high-efficiency mechanical tool as a buffer layer for the deposition of the diamond coating.

Crystallization of sputter-deposited amorphous Ge films by electron irradiation: Effect of low-flux pre-irradiation

We investigated the effect of low-flux electron irradiation with 125 keV to sputter-deposited amorphous germanium on the amorphous structure and electron-induced crystallization microstructure by TEM following our previous study on the effect of aging at room temperature. In samples aged for 3 days, coarse, spherical particles about 100 nm in diameter appear dominantly. By low-flux pre-irradiation to the samples, a reduction in the size and number of coarse particles, embedded in the matrix with fine nanograins of the diamond cubic structure, was noted with the increase in fluence. The crystal structure of these coarse particles was found to be not cubic but hexagonal. In samples aged for 4 months, a similar tendency was observed. In samples aged for 7 months, on the other hand, the homogeneous diamond cubic structured nanograins were unchanged by pre-irradiation. These results indicate that pre-irradiation as well as aging modifies the amorphous structure, preventing the appearance of a hexagonal phase. The elimination of a certain amount of medium-range ordered clusters by pre-irradiation, included in as-deposited samples and the samples aged for 4 months, apparently gives rise to a reduction in the size and number of coarse particles with a metastable hexagonal structure.

Simulation of temperature distribution in hot filament chemical vapor deposition diamond films growth on SiC seals

In this study, the temperature and gas velocity distributions in hot filament chemical vapor deposition (HFCVD) diamond film growth on the end surfaces of seals are simulated by the finite volume method. The influence of filament diameter, filament separation and rotational speed of the substrates is considered. Firstly, the simulation model is established by simplifying operating conditions to simulate the temperature and gas velocity distributions. Thereafter, the deposition parameters are optimized as 0.6mm filament diameter, 18mm filament separation and 5 r/min rotational speed to get the uniform temperature distribution. Under the influence of the rotational speed, the difference between temperature gradients along the directions perpendicular to the filament and parallel to the filament becomes narrow, it is consistent with the actual condition, and the maximum temperature difference on the substrates decreases to 7.4 ◦C. Furthermore, the effect of the rotational speed on the gas velocity distribution is studied. Finally, diamond films are deposited on the end surfaces of SiC seals with the optimized deposition parameters. The characterizations by scanning electron microscopy (SEM) and Raman spectroscopy exhibit a layer of homogeneous diamond films with fine-faceted crystals and uniform thickness. The results validate the simulation model.

Improving the long-term stability of Ti6Al4V abutment screw by coating micro/nano-crystalline diamond films

Abutment screw loosening is the most common complication of implanting teeth. Aimed at improving the long-term stability of them, well-adherent and homogeneous micro-crystalline diamond (MCD) and nano-crystalline diamond (NCD) were deposited on DIO® (Dong Seo, Korea) abutment screws using a hot filament chemical vapor deposition (HFCVD) system. Compared with bare DIO® screws, diamond coated ones showed higher post reverse toque values than the bare ones (p<0.05) after cyclic loading one million times under 100N, and no obvious flaking happened after loading test. Diamond coated disks showed lower friction coefficients of 0.15 and 0.18 in artificial saliva when countered with ZrO2 than that of bare Ti6Al4V disks of 0.40. Though higher cell apoptosis rate was observed on film coated disks, but no significant difference between MCD group and NCD group. And the cytotoxicity of diamond films was acceptable for the fact that the cell viability of them was still higher than 70% after cultured for 72h. It can be inferred that coating diamond films might be a promising modification method for Ti6Al4V abutment screws.

Epitaxy of iridium on SrTiO3/Si (001): A promising scalable substrate for diamond heteroepitaxy

Iridium epitaxy on SrTiO3/Si (001) was investigated using field emission scanning electron microscopy (FE-SEM), spectroscopic ellipsometry, X-ray diffraction (XRD) and atomic force microscopy (AFM). Thermal stability of SrTiO3 buffer layers (12–40nm thick) was first investigated by annealing at different temperatures (620°C–920°C) under vacuum to optimize iridium epitaxy conditions. The surface morphology was monitored by FE-SEM and optical constants by spectroscopic ellipsometry. Iridium films were then deposited and their morphology and crystalline quality were evaluated by FE-SEM and XRD. It was found that iridium epitaxy is optimized at 660°C on SrTiO3 films thicker than ~30nm. The polar and azimuthal mosaicities of the iridium films on SrTiO3/Si (001) were 0.3° and 0.1°, respectively. These epitaxial iridium films were further used for diamond heteroepitaxy. The bias enhanced nucleation (BEN) treatment resulted in highly homogeneous and dense diamond domains. Heteroepitaxial diamond films were further grown by microwave plasma enhanced chemical vapor deposition (MPCVD) on 7×7mm2 Ir/SrTiO3/Si (001) substrates and characterized by XRD.

Layer Protecting the Surface of Zirconium Used in Nuclear Reactors.

Zirconium alloys have very useful properties for nuclear facilities applications having low absorption cross-section of thermal electrons, high ductility, hardness and corrosion resistance. However, there is also a significant disadvantage: it reacts with water steam and during this (oxidative) reaction it releases hydrogen gas, which partly diffuses into the alloy forming zirconium hydrides. A new strategy for surface protection of zirconium alloys against undesirable oxidation in nuclear reactors by polycrystalline diamond film has been patented- Czech patent 305059: Layer protecting the surface of zirconium alloys used in nuclear reactors and PCT patent: Layer for protecting surface of zirconium alloys (Patent Number: WO2015039636-A1). The zirconium alloy surface was covered by polycrystalline diamond layer grown in plasma enhanced chemical vapor deposition apparatus with linear antenna delivery system. Substantial progress in the description and understanding of the polycrystalline diamond/ zirconium alloys interface and material properties under standard and nuclear reactors conditions (irradiation, hot steam oxidation experiments and heating-quenching cycles) was made. In addition, process technology for the deposition of protective polycrystalline diamond films onto the surface of zirconium alloys was optimized. Zircaloy2 nuclear fuel pins were covered by 300 nm thick protective polycrystalline diamond layer (PCD) using plasma enhanced chemical vapor deposition apparatus with linear antenna delivery system. The polycrystalline diamond layer protects the zirconium alloy surface against undesirable oxidation and consolidates its chemical stability while preserving its functionality. PCD covered Zircaloy2 and standard Zircaloy2 pins were for 30 min. oxidized in 1100°C hot steam. Under these conditions α phase of zirconium changes to β phase (more opened for oxygen/hydrogen diffusion). PCD anticorrosion protection of Zircaloy nuclear fuel assemblies can significantly prolong lifetime of Zirconium alloy in nuclear reactors even above Zirconium phase transition temperatures. Even after ion beam irradiation (10 dpa, 3 MeV Fe(2+)) the diamond film still shows satisfactory structural integrity with both sp(3) and sp(2) carbon phases. Zircaloy2 under the carbon-based protective layer after hot steam oxidation test differed from the original Zircaloy2 material composition only very slightly, proving that the diamond coating increases the material resistance to high temperature oxidation. Zirconium alloys nuclear fuel pins' surfaces were covered by compact and homogeneous polycrystalline diamond layers consisting of sp(3) and sp(2) carbon phases with a high crystalline diamond content and low roughness. Diamond withstands very high temperatures, has excellent thermal conductivity and low chemical reactivity, it does not degrade over time and (important for the nuclear fuel cladding) being pure carbon, it has perfect neutron cross-section properties. Moreover, polycrystalline diamond layers consisting of crystalline (sp(3)) and amorphous (sp(2)) carbon phases could have suitable thermal expansion. Zirconium alloys coated with polycrystalline diamond film are protected against undesirable changes and processes. Further, the polycrystalline diamond layer prevents the reaction between the alloy surface and water vapor. During such reaction, water molecules dissociate and initiate formation of zirconium dioxide and hydrogen, accompanied by the release of large amount of heat. Thus the protective layer prevents the formation of hydrogen and the release of reaction heat. Few relevant patents to the topic have been reviewed and cited.

Fabrication of diamond-coated germanium ATR prisms for IR-spectroscopy

Monocrystalline germanium is considered a highly useful material for infrared optical applications due to its relatively low price, low toxicity and high optical transparency in the infrared spectral range (5500–870cm−1). However, it is limited by its low chemical, mechanical, and thermal stability. The thin film diamond coating can provide a mechanical protection of a Ge surface against scratching, chemical protection against solutions, and make a well-defined hydrophilic/hydrophobic surface. Here, we compare low temperature (250–400°C) diamond growth on Ge substrates and attenuated total reflection prisms, using a chemical vapor deposition in linear antenna microwave plasma and focused microwave plasma reactors. We show that by employing a thin amorphous silicon interlayer (20–30nm), a homogeneous diamond coating with no degradation of the Ge surface is achieved. The infrared spectroscopy of proteins adsorbed on the diamond coated Ge prism demonstrates usability and advantages in comparison with bare Si or Ge prisms and even with the diamond-coated Si prism.