Structure evolution in Ag/Ni multilayers grown by ultra high vacuum DC magnetron sputtering

Deposition of hydrogenated amorphous carbon nitride films by dielectric barrier discharge plasmas

Formation of nanocrystalline TiN at low temperatures was demonstrated by combining Pulsed Laser Deposition (PLD) and ion implantation techniques. The Ti films of nominal thickness approximatly 250 nm were deposited at a substrate temperature of 200 degrees C by ablating a high pure titanium target in UHV conditions using a nanosecond pulsed Nd:YAG laser operating at 1064 nm. These films were implanted with 100 keV N+ ions with fluence ranging from 1.0 x 10(16) ions/cm2 to 1.0 x 10(17) ions/cm2 The structural, compositional and morphological evolutions were tracked using Transmission Electron Microscopy (TEM), Secondary Ion Mass Spectrometry (SIMS) and Atomic Force Microscopy (AFM), respectively. TEM analysis revealed that the as-deposited titanium film is an fcc phase. With increasing ion fluence, its structure becomes amorphous phase before precipitation of nanocrystalline fcc TIN phase. Compositional depth profiles obtained from SIMS have shown the extent of nitrogen concentration gradient in the implantation zone. Both as-deposited and ion implanted films showed much higher hardness as compared to the bulk titanium. AFM studies revealed a gradual increase in surface roughness leading to surface patterning with increase in ion fluence.

PURPOSE: The goal of our study was to investigate the changes in enamel surface roughess induced by the application of different chemical substances by atomic force microscopy and scanning electron microscopy. METHOD: Five sound human first upper premolar teeth were chosen for the study. The buccal surface of each tooth was treated with a different chemical agent as follows: Sample 1 - 38% phosphoric acid etching (30s) , sample 2 - no surface treatment (control sample), 3 - bleaching with 37.5 % hydrogen peroxide (according to the manufacturer's instructions), 4 - conditioning with a self-etching primer (15 s), 5 - 9.6 % hydrofluoric acid etching (30s). All samples were investigated by atomic force microscopy in a non-contact mode and by scanning electron microscopy. Several images were obtained for each sample, showing evident differences regarding enamel surface morphology. The mean surface roughness and the mean square roughness were calculated and compared. RESULTS: All chemical substances led to an increased surface roughness. Phosphoric acid led to the highest roughness while the control sample showed the lowest. Hydrofluoric acid also led to an increase in surface roughness but its effects have yet to be investigated due to its potential toxicity. CONCLUSIONS: By treating the human enamel with the above mentioned chemical compounds a negative microretentive surface is obtained, with a morphology depending on the applied substance.

c-axis-oriented aluminum nitride (AlN) films were successfully prepared on a Y-128° LiNbO3 substrate by rf magnetron sputtering. The dependence between sputtering pressures and the physical structures of the films (crystalline structure and micromorphology) was investigated by x-ray diffraction (XRD) and atomic force microscopy (AFM). The result showed that the higher c-axis-oriented AlN films appeared at lower sputtering pressures and the uneven grain structures existed as multioriented XRD patterns appeared in the high sputtering pressure region (5–9 mTorr). The best orientation and microstructure of the films was prepared at 3 mTorr.

The reactivity of liquid hydrazine (N2H4) with respect to H-, Cl-, and Br-terminated Si(100) surfaces was investigated to uncover the principles of nitrogen incorporation into the interface. This process has important implications in a wide variety of applications, including semiconductor surface passivation and functionalization, nitride growth, and many others. The use of hydrazine as a precursor allows for reactions that exclude carbon and oxygen, the primary sources of contamination in processing. In this work, the reactivity of N2H4 with H- and Cl-terminated surfaces prepared by traditional solvent-based methods and with a Br-terminated Si(100) prepared in ultrahigh vacuum was compared. The reactions were studied with X-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy, and the observations were supported by computational investigations. The H-terminated surface led to the highest level of nitrogen incorporation; however, the process proceeds with increasing surface roughness, suggesting possible etching or replacement reactions. In the case of Cl-terminated (predominantly dichloride) and Br-terminated (monobromide) surfaces, the amount of nitrogen incorporation on both surfaces after the reaction with hydrazine was very similar despite the differences in preparation, initial structure, and chemical composition. Density functional theory was used to propose the possible surface structures and to analyze surface reactivity.

Barrel style centrifugal compressors are widely used for high pressure gas compression applications in the oil and gas industry. Using a modular rotor in a high pressure centrifugal compressor for Oil and Gas Service is a method that is distinctly different from ubiquitous solid shaft machine designs. It is accepted in the governing standards, for example API 617, and allows for significant flexibility under changing operating requirements. Using a modular rotor allows to avoid splitting diaphragms, but it also requires different assembly, balancing and test methods. The machine described in this study is a single compartment compressor capable of 340 bar discharge pressure. The study provides aerodynamic test data for a series of closed loop tests at discharge pressures of over 220 bar, using Nitrogen, CO2 and natural gas as test gases, to validate compressor performance, rotordynamic stability and mechanical integrity. An important feature of the test campaign is the detailed evaluation of the transient behavior during tests to verify the machine integrity at rapid shutdowns at high discharge pressures. The paper also discusses the applications for such centrifugal compressors in the oil and gas industry, considerations on standardized designs, and its integration in a modular design system.

Aluminium gallium nitride (AlGaN) thin films provide promise for a variety of electronic devices due to their wide energy bandgap, which ranges from 3.11 – 6.40 eV. Here, a co-sputtering approach utilising the RF and HiPIMS power supply of magnetron sputtering is used to deposit the AlGaN thin films. To examine their impact on the structural characteristics and morphology of the thin films, the AlGaN thin films were deposited under various sputtering pressures using the co-sputtering technique. Following that, the films were examined using X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and surface profiling to determine their characteristics. XRD shows the polycrystalline AlGaN with (100), (101), (102), and (110) plane for the AlGaN deposited at a sputtering pressure of 3 mTorr and 5 mTorr with FWHM 0.622° and 0.732°, respectively. The increasing the sputtering pressure to 5 mTorr is found to improve the crystallinity as well as the thickness of the AlGaN thin films from 234.27 – 1479.37 nm. AFM examination of the AlGaN film revealed a trend of increasing roughness and grain size together up to 3.25 nm and 47.22 nm respectively, with rising sputtering pressure from 1 – 7 mTorr. The co-sputtering of AlGaN can be successfully demonstrated in this study, and it is also shown that the sputtering pressure has a substantial impact on the development of AlGaN thin films produced using this technology.

Effect of sputtering pressure on the surface topography, structure, wettability and tribological performance of DLC films coated on rubber by magnetron sputtering

The microstructural and mechanical stabilities of a Nextel 720 (alumina+mullite) fiber-reinforced, alumina matrix composite were evaluated following exposure of the material to a high H2O pressure (to simulate a gas turbine combustor environment) in Oak Ridge National Laboratory’s (ORNL’s) high temperature, high pressure facility (Keiser Rigs). Coupons were exposed at 1135°C and 1200°C in a high-pressure (10 atm) furnace containing 10% water vapor for 1000, 2000, and 3000 h. Extensive microstructural characterization was conducted after each exposure to evaluate fiber and matrix stabilities as a function of exposure time and temperature. Retained tensile strengths were also measured and compared to baseline properties following each exposure. It was found that there was no significant change in the composite microstructure or tensile strength after long-term exposure in the Keiser Rig at 1135°C, whereas significant Nextel 720 fiber degradation (grain growth and increased surface roughness) occurred during exposure for 3000 h at 1200°C. Statistical variations in the mean strength values between the as-processed and exposed composites indicated little change in strength, however. The composite degradation was primarily thermal and the addition of H2O had little effect on changing or accelerating these effects.

Since its invention in 1986, atomic force microscopy (AFM) has been used mainly in ambient conditions. Recent advances in instrumentation have fostered the application of AFM in ultrahigh vacuum (UHV). AFM experiments performed in UHV have led to a better understanding of the tip-sample interaction. This article reviews the theory related to achieving true atomic resolution of AFM in UHV in both contact- and noncontact-modes. Preliminary experimental results with unprecedented resolution on KCl and Si (111)7×7 achieved by noncontact AFM in UHV are presented.

Structural and optical properties of sputtered Titania films

Synchrotron-radiation photoelectron spectroscopy is used to study the valence-band structure and the core-level photoemission spectra of HfO2 ultrathin films grown onto SiO2∕Si substrates by atomic layer deposition (ALD). We determine the band offsets (valence and conduction) of HfO2 to Si as a function of postdeposition annealing treatments (under an inert N2 atmosphere or in situ in ultrahigh vacuum) and find a significant evolution, the conduction-band offset remaining larger than 1.5eV. The Si2p and the Hf4f core-level spectra give detailed information on the composition and the spatial extent of the interfacial Hf silicate layer formed between the SiO2 bottom oxide and the HfO2 ALD thin film. By a quantitative treatment of the Si2p core-level intensities, we examine the thermal stability of the interface silicate after postdeposition annealing under N2 and in situ annealing in ultrahigh vacuum (UHV), both at 800°C. The as-deposited layer gives rise to a HfO2∕Hf0.35Si0.65O2∕SiO2 stack with corresponding thicknesses of 0.74∕0.51∕0.73nm. After postdeposition annealing at 800°C in a N2 atmosphere, this becomes a HfO2∕Hf0.31Si0.69O2∕SiO2 stack with corresponding thicknesses of 0.71:0.58:0.91nm. In situ annealing in UHV, on the other hand, gives a HfO2∕Hf0.35Si0.65O2∕SiO2 stack with corresponding thicknesses of 0.65:0.70:0.76nm. The former favors an extension of both the silicate and the SiO2 interface layers, whereas the latter develops only the silicate layer.

The descriptions of the new products listed in this section are based on information supplied to us by the manufacturers. Physics Today can assume no responsibility for their accuracy. For more information about a particular product, visit the website at the end of the product description. Magnetic force microscopy probesSection:ChooseTop of pageMagnetic force microscopy... <<Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLESNANOSENSORS has introduced a new series of six silicon probes for magnetic force microscopy that make possible the visualization of magnetic domains. The probes are optimized for high sensitivity and enable tapping mode and noncontact and lift modes in air. The standard MFM probes feature a hard magnetic coating for high magnetic contrast and high lateral resolution. The low-momentum probes are designed for reduced disturbance of the magnetic sample by the tip and for enhanced lateral resolution. Low-coercivity MFM probes are coated with a soft magnetic thin film to allow the measurement of domains in soft magnetic samples. For high-resolution magnetic imaging, NANOSENSORS offers the SuperSharp-Silicon tip. Two types of probes have been developed for use in ultrahigh vacuum. NANOSENSORS, Rue Jaquet-Droz 1, CP 216, CH-2002 Neuchatel, Switzerland, http://www.nanosensors.com See www.pt.ims.ca/12307-131 Silver nanoparticles Section:ChooseTop of pageMagnetic force microscopy...Silver nanoparticles <<Atomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLESAmerican Elements has announced expansion of the manufacture of silver oxalate, a precursor for the production of silver nanoparticles. The nanoparticles, nanodots, and nanopowder can be either spherical high-surface-area metal particles, typically 10-, 40-, and 80-nm o.d., with specific surface area in the 30–60 range m2/g, or flakes with an average particle size of 2–10 µm, with an SSA of approximately 40–80 m2/g. The silver particles are available in high purity and ultrahigh purity and in coated and dispersed forms. Applications for the product include as an antimicrobial, antibacterial, antiviral, antibiotic, and antifungal agent when incorporated in coatings, nanofibers, plastics, soap, textiles, and self-cleaning fabrics. It is also used in nanowire and certain catalyst applications. American Elements, 1093 Broxton Avenue, Suite 2000, Los Angeles, CA 90024, http://www.americanelements.com See www.pt.ims.ca/12307-132 Atomic force microscope Section:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscope <<Scanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLESPacific Nanotechnology has developed the Nano-DST, a complete atomic force microscope (AFM) system that includes advanced control software, a high-performance electronic controller, a versatile stage, and a vibration solution. A dual scanner control enables two scanners to be driven individually or simultaneously to perform rapid scanning and panning. With the company’s flexure scanner, which uses 3D calibration sensors, optional scan ranges as high as 350 µm are possible; 24-bit scan control and 400-MHz high-stability modulation electronics are included. The Nano-DST stage is constructed with a precision granite base and a gantry that supports a video optical microscope, light lever AFM scanner, and the high-speed sample rapid scanner. The stage features seven stepper motors that control the sample position, optics zoom, and focus. Pacific Nanotechnology Inc, 3350 Scott Boulevard, Suite 29, Santa Clara, CA 95054, http://www.pacificnano.com See http://www.pt.ims.ca/12307-133 Scanner for nanotechnology Section:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog... <<Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLESPhysik Instrumente is offering the P-363 PicoCube XY/XYZ, a high-performance, closed-loop piezo scanning system designed for atomic force, scanning probe, and scanning tunneling microscopy. It combines the ultralow-inertia, high-speed piezo scanner with noncontact, direct-measuring, parallel metrology capacitive position sensors capable of 50-pm resolution. The sensors measure the actual distance between the fixed frame and the moving part of the stage, which results in a stiffer, faster-responding servo-loop. The very fast xyz piezo drives offer resonant frequencies of 9.8 kHz in z and greater than 3 kHz in x and y. The high frequency and high-bandwidth capacitive feedback allow step and settle to 1% accuracy in as little as 1 ms. The company can now provide the E-536 driver/controller for use with the PicoCube. Physik Instrumente LP, 16 Albert Street, Auburn, MA 01501, http://www.pi-usa.us See www.pt.ims.ca/12307-134 Nanoimprint lithography Section:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithography <<Digital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLESMolecular Imprints has introduced the Imprio 1100 system, which provides fully automated nanoimprint lithography. The system combines the resolution and CD control of e-beam lithography with the throughput, overlay, and operating simplicity of a mask aligner, and it can be configured to accept 25- to 150-nm substrates. The Imprio 1100 delivers cost-effective patterning of sub-50 nm features on the fragile, nonflat substrates used in the compound semiconductor industry. The same processes can also be used to pattern larger features such as laser diode ridges and diffractive optical elements with high pattern fidelity. The system is ideally suited for application in LEDs, optical components requiring fine-resolution patterning and 3D features, and high-density disk substrates for hard disk drives. Molecular Imprints Inc, 1807 West Braker Lane, Building C-100, Austin, TX 78758-3605, http://www.molecularimprints.com See www.pt.ims.ca/12307-135 Digital microscopeSection:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscope <<X-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLESThe KH-7700 digital microscope from Hirox Inc combines as one unit a digital camera, light source, integrated LCD monitor, computer, and software. The camera incorporates a CCD image sensor with approximately 2.11 million pixels and provides a rate of 15 frames/s. It offers a still image capture of up to 30 million pixels and dynamic image recording with selectable resolution. The light source is a 60-W short-arc metal halide lamp with an average life of 4000 hours. A modular lens system with 1× to 7000× magnification is optimized for the CCD sensor and offers viewing from straight and oblique angles. For 2D and 3D measurements of height and volume, an autocalibration select feature enables users to zoom in and out while the scale and calibration in the unit changes accordingly. The KH-7700 has 3D image rendering software with profiling that uses split images and image comparison. Hirox-USA Inc, 1060 Main Street, Suite 302, River Edge, NJ 07661, http://www.hirox-usa.com See www.pt.ims.ca/12307-136 X-ray source for structural biologySection:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur... <<Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLESRigaku Americas Corp has announced the FR-E+ SuperBright, an ultrabright, microfocus rotating anode x-ray source for structural biology. With an intensity up to 1.6 ×1011 x-rays/mm2/s, the brightness of the new source exceeds some second-generation synchrotron beamlines; the company claims that the new device is the most intense home laboratory x-ray source now available for macromolecular crystallography. The FR-E+ SuperBright features a true 70 µm × 70 µm focal spot, reportedly the smallest available in a rotating anode design. The beam is ideally suited to the tiny crystals typically encountered in current structural biology research. The new system can be supplied in several dual-wavelength configurations, including one using copper and chromium. Rigaku Americas Corporation, 9009 New Trails Drive, The Woodlands, TX 77381-5209, http://www.rigaku.com See www.pt.ims.ca/12307-137 Spectroscopic ellipsometer Section:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete... <<Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLES Ocean Optics’ SpecEl-2000-VIS is a benchtop spectroscopic ellipsometer that uses polarized light reflected from the surface of a substrate to measure thin films. It provides fast, precise determination of layer thickness, refractive index, absorption, and components ratio and is well suited for semitransparent flat samples such as wafers and glass plates. Compared with reflectometry, spectroscopic ellipsometry measures relative changes in the phase and amplitude of the light instead of absolute intensity. Depending on the layer and substrate material, the SpecEl can detect over the full 450- to 900-nm spectral range layer thicknesses between 1 nm and 5 µm and refractive indices to ±0.005°. The software enables experiment methods to be configured and saved for one-step analysis. Ocean Optics Inc, 830 Douglas Avenue, Dunedin, FL 34698, http://www.oceanoptics.com See www.pt.ims.ca/12307-138 Wafer loader for microscopy Section:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco... <<Camera for biofluorescenc...Microfluidic componentsNew literatureCITING ARTICLESMcBain Instruments is offering a newly designed laboratory tool, the Wafer Handler WL150 and WL200 series of semiautomatic wafer inspection systems. The portable apparatus offers high throughput at 750 wafers/h with smooth handling of wafer sizes up to 8 in.; the company’s new wafer cassettes accommodate either 3–6 in. (WL150) or 5–8 in. (WL200) sizes. The class 1 clean-room-compatible wafer handler features smart stepper motors for the drive axis motors that provide stall and fault detection, linear stages for smooth and repeatable action, and vacuum touch end effectors with sensing capabilities. The device facilitates safer wafer handling with a spring-loaded counterbalance to support the weight without overloading the z-axis mechanism. McBain Instruments, 9601 Variel Avenue, Chatsworth, CA 91311, http://www.mcbaininstruments.com See www.pt.ims.ca/12307-139 Camera for biofluorescence microscopy Section:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc... <<Microfluidic componentsNew literatureCITING ARTICLESPhotron has developed the FocusScope SV200-i, a new slow-motion video system for the study of extreme low-light biofluorescence and microscope recording at rates up to 2000 frames/s. Other applications include high-speed imaging of blood cells and quantum-dot response measurements. The camera’s image intensifier (a luminous gain of 2.2 × 104 lm/m2/lx) is bonded directly to the CMOS sensor and provides 512 × 512 pixel resolution. The gallium arsenide phosphide photocathode delivers a broad spectral response over the 280–720 nm spectral range with a peak sensitivity at 530 nm. Intensifier overbrightness protection is enabled through phosphor-surface current detection. Additional features of the FocusScope SV200-i are low-light-level framing and gray-scale enhancement. Photron USA Inc, 9520 Padgett Street, Suite 110, San Diego, CA 92126-4446, http://www.photron.com See www.pt.ims.ca/12307-140 Microfluidic componentsSection:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic components <<New literatureCITING ARTICLESLabSmith has introduced its CapTite microfluidic series of components for fast assembly of microfluidic setups. The components, licensed from Sandia National Laboratories, are designed for construction using 360-µm capillary tubing and include breadboards, valves, tees and ferrules, refillable microliter volume cartridges, Luer-Lock connectors to interface with standard syringe pumps, and bonded-port connectors to route fluids through and between microfluidic chips. The compact components are designed for leak-free connectivity, even at high pressures, and for low dead volumes and easy cleaning. Complete microfluidic construction kits are available; users can choose from single user, capillary interface, and chip interface types. LabSmith Inc, 7665 Hawthorne Avenue, Livermore, CA 94550, http://www.labsmith.com See www.pt.ims.ca/12307-141 New literatureSection:ChooseTop of pageMagnetic force microscopy...Silver nanoparticlesAtomic force microscopeScanner for nanotechnolog...Nanoimprint lithographyDigital microscopeX-ray source for structur...Spectroscopic ellipsomete...Wafer loader for microsco...Camera for biofluorescenc...Microfluidic componentsNew literature <<CITING ARTICLESInnoCal, an accredited metrology laboratory, has issued a service brochure that provides a comprehensive explanation of its many traceable calibration and repair services for a wide range of instrumentation. InnoCal, 625 East Bunker Court, M/S 14, Vernon Hills, IL 60061-1844, http://www.innocalsolutions.com ▪ See www.pt.ims.ca/12307-142 © 2007 American Institute of Physics.

Introduction: Laser irradiation of dentin surface can affect its surface topography and roughness. Atomic force microscopy (AFM) is among the most efficient tools for determination of surface topography of natural biomolecules in nano-scales. Surface roughness affects plaque retention especially in the cervical region. This study aimed to assess and compare the obstruction of dentinal tubules and dentin surface roughness after irradiation of erbium: yttrium aluminum garnet (Er:YAG ) and CO2 lasers for treatment of dentin hypersensitivity (DH). Methods: Five disc-shaped samples measuring 3 mm in thickness were fabricated by horizontal sectioning of the cervical area of five extracted human molars using a low speed saw. Each disc was divided into 3 segments by a bur under water coolant. The three segments of each disc were placed on a glass slide. First segment: No intervention (control group). Second segment: Er:YAG laser irradiation (2940 nm, 50 mJ, 10 Hz and 0.5 W, 30 seconds) along with water coolant. Third segment: CO2 laser irradiation (10600 nm, 80 Hz, 0.3 W, 30 seconds) along with water coolant. After that, the surfaces underwent non-contact AFM. The diameters of dentinal tubules as well as surface roughness were then measured and statistically analyzed using repeated measures ANOVA. Results: The surface roughness parameters (Ra, Rq) showed increased roughness after laser irradiation and this increase in roughness after Er:YAG laser application was significant compared to the control group (P=0.048). However, CO2 laser caused no significant change in surface roughness. Also, after Er:YAG laser application, fewer open dentinal tubules were observed and the remaining open tubules had a smaller diameter. Conclusion: Based on the results, Er:YAG laser irradiation obstructs the dentinal tubules and increases the dentin surface roughness. This increase in surface roughness can cause microbial plaque retention and increase the risk of caries and periodontal disease. Application of CO2 laser (compared to Er:YAG) lead to slight but clinically significant obstruction of dentinal tubules and surface roughness.

Most of the molybdenum (Mo) bilayer films are deposited by direct current (DC) magnetron sputtering at the bottom and the top layer (DC/DC). However, the deposition of Mo bilayer film by radio frequency (RF) Mo bottom layer and DC Mo top layer magnetron sputtering has been less studied by researchers. In this paper, the bottom layer of Mo bilayer film was deposited by RF magnetron sputtering to maintain its good adhesion and high reflectance, and the top layer was deposited by DC magnetron sputtering to obtain good conductivity (RF/DC). Generally, the bottom layer sputtering pressure is relatively random, in this paper, the effects of the bottom layer RF sputtering pressures on the microstructures and properties of Mo bilayer films were first studied in detail. Next, in order to further improve their properties, the as-prepared Mo bilayer films at 0.4 Pa bottom layer RF sputtering pressure were annealed at different temperatures and then investigated. Specifically, Mo bilayer films were deposited on soda-lime glass substrates by RF/DC magnetron sputtering at different bottom layer RF sputtering pressures in the range of 0.4–1.2 Pa, the powers of bottom layer RF sputtering and top layer DC sputtering were 120 W and 100 W, respectively. Then, Mo bilayer films, prepared at a bottom layer sputtering pressure of 0.4 Pa and top layer sputtering pressure of 0.3 Pa, were annealed for 30 min at various temperatures in the range of 100–400 °C. The effects of bottom layer sputtering pressures and the annealing temperatures on the microstructures, electrical and optical properties of Mo bilayer films were clarified by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), atomic-force microscopy (AFM), and ultraviolet (UV)-visible spectra, respectively. It is shown that with decreasing bottom layer sputtering pressure from 1.2 to 0.4 Pa and increasing annealing temperature from 100 to 400 °C, the crystallinity, electrical and optical properties of Mo bilayer films were improved correspondingly. The optimized Mo bilayer film was prepared at the top layer sputtering pressure of 0.3 Pa, the bottom layer sputtering pressure of 0.4 Pa and the annealing temperature of 400 °C. The extremely low resistivity of 0.92 × 10−5 Ω.cm was obtained. The photo-conversion efficiency of copper indium gallium selenium (CIGS) solar cell with the optimized Mo bilayer film as electrode was up to as high as 13.5%.