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Acoustic tweezers hold great promise for potential applications in cell sorting due to their noncontact, noninvasive, and simple characteristics. Acoustic tweezers, however, have difficulty in separating the cells of the same size distribution, which hampers their applications. In this paper, we demonstrate that assisted by the targeted microbubble, two kinds of cells with an overlap in size distribution can be efficiently separated by surface acoustic waves. By specifically adhering the targeted microbubbles to MDA-MB-231 cells, the acoustic sensitivity of cells can be improved significantly, leading to the isolation of MDA-MB-231 from MCF-7 cells with an efficiency of 91.2 ± 3.4%. This method extends the diversity of acoustic separation and is capable of separation of particles with the same density and diameter, proving a strategy for specific cell sorting.

Using plasma-enhanced chemical vapor deposition (PECVD) based on fluorine chemistry, the limitations hindering the practical use of cubic boron nitride (cBN) films in mechanical applications have been overcome. The CVD method presented is characteristic with (a) the direct cBN growth on diamond without soft, noncubic BN interface layers, (b) the synthesis of cBN films with extraordinary adhesion to the substrates and high mechanical properties, and (c) the scalable process providing thick, large-area cBN films at high deposition rate even on rough and untreated surfaces. These prime technological properties open the route to the mechanical exploitation of cBN films, particularly in tribological and tool applications. The reduction of the bias voltage in the PECVD process presented to a value of −20V not only provides high-quality films, but also gives physical insight into the cBN growth mechanism.

A structuring method capable of producing uniform, large-area cone arrays of diamond films was developed. The technique employs bias-assisted reactive ion etching and is applicable to any structure of diamond films ranging from microcrystalline to nanocrystalline. Variation of the etching conditions enables control of the cone density, geometry, and height. Surface nanostructuring of cone arrays significantly improves the field emission properties of diamond films of all kinds. The turn on field is reduced to 6 and 10 V/μm for nanodiamond and microdiamond films, respectively, (compared to >25 V/μm for as deposited surfaces). Lower cone density yields better field electron emission (lower turn-on electrical field) due to the screening in high-density cone arrays. The field emission properties are determined by both the enhancement factor of the cone array and the emitting properties of the material. The field electron emission properties of nanodiamond arrays are better than cone arrays of single crystalli...

One of the major problems in material science has been the difficulty in modification of the most endurable material, diamond, due to its extreme hardness and chemical inertness. Here, we report the development of a conical structure of diamond by performing bias-assisted reactive ion etching in hydrogen plasma. The diamond cones produced by this method are uniformly distributed over large areas on silicon substrates. Each cone was identified to be a single crystal with an apical angle as small as 28° and a very sharp tip (tip radii ∼2 nm). Their [001] axes are perpendicular to the substrate surface and parallel to each other. Such striking structures of individual single-crystal diamond cones and their arrays, in addition to their scientific value, may lead to a breakthrough in the design of high-performance mechanical and electronic devices.

In an attempt to suppress the dark current, the barrier layer engineer for solution-processed PbSe colloidal quantum-dot (CQD) photodetectors has been investigated in the present study. It was found that the dark current can be significantly suppressed by implementing two types of carrier blocking layers, namely, hole blocking layer and electron blocking layer, sandwiched in between two active PbSe CQD layers. Meanwhile no adverse impact has been observed for the photo current. Our study suggests that this improvement resides on the transport pathway created via carrier recombination at intermediate layer, which provides wide implications for the suppression of dark current for infrared photodetectors.

Electronic structures of copper hexadecafluorophthalocyanine (F16CuPc)/graphene with different defect density were studied with ultra-violet photoelectron spectroscopy. We showed that the charge transfer interaction and charge flow direction can be interestingly tuned by controlling the defect density of graphene through time-controlled H2 plasma treatment. By increasing the treatment time of H2 plasma from 30 s to 5 min, both the interface surface dipole and the electron transporting barrier at F16CuPc/graphene interface are significantly reduced from 0.86 to 0.56 eV and 0.71 to 0.29 eV, respectively. These results suggested that graphene's defect control is a simple approach for tuning electronic properties of organic/graphene interfaces.

Boron carbon nitride (BCN) films were synthesized on Si (100) and fused silica substrates by radio-frequency magnetron sputtering from a B4C target in an Ar/N2 gas mixture. The BCN films were amorphous, and they exhibited an optical band gap of ∼1.0 eV and p-type conductivity. The BCN films were over-coated with ZnO nanorod arrays using hydrothermal synthesis to form BCN/ZnO-nanorods p-n heterojunctions, exhibiting a rectification ratio of 1500 at bias voltages of ±5 V.

A new phenomenon of diamond growth was observed. (001) oriented diamond layers can be grown on a (111) diamond face in a bias‐assisted chemical vapor deposition process. The growth characteristics were investigated by means of scanning electron microscopy and Raman spectroscopy. It was found that, due to the ion bombardment, the epitaxial growth of the (111) diamond face was interrupted and a secondary nucleation occurred. This ion‐bombardment‐induced secondary nucleation leads to the growth of a top layer with a nonparallel orientation relationship with the substrate.

The influence of ion bombardment during microwave plasma chemical vapor deposition (CVD) on diamond film orientation has been investigated. Two interesting findings were obtained: (1) The [001] axes of the grown diamond grains are always along the ion flow direction, perpendicular to the substrate and independent of the crystal orientation of the substrates and (2) for the crystallites which are homoepitaxially grown on the (001) diamond faces parallel to the substrate slight misorientations were found. These new findings confirm the role of ion impact in diamond CVD and can help us to understand the basic mechanism responsible for the crystal orientation in heteroepitaxial diamond films prepared using bias‐enhanced nucleation.

Si ion implantation with a set of ion energies and ion doses was carried out to dope hexagonal boron nitride (hBN) thin films synthesized by radio-frequency magnetron sputtering. Hall effect measurements revealed n-type conduction with a low resistivity of 0.5 Ω cm at room temperature, corresponding to an electron concentration of 2.0 × 1019 cm−3 and a mobility of 0.6 cm2/V s. Temperature-dependent resistivity measurements in a wide temperature range from 50 to 800 K demonstrated two shallow donor levels in the hBN band gap induced by Si doping, which was in consistence with the theoretical calculation by density function theory.

A binder-free, high-rate Ge-three dimensional (3D) graphene composite was synthesized by directly depositing Ge film atop 3D graphene grown by microwave plasma chemical vapor deposition on Ni substrate. The Ge-3D graphene structure demonstrates excellent electrochemical performance as a lithium ion battery (LIB) anode with a reversible capacity of 1140 mAh g−1 at 1/3C over 100 cycles and 835 mAh g−1 at 8C after 60 cycles, and significantly a discharge capacity of 186 mAh g−1 was still achieved at 32C. The high capacity and outstanding stability of the Ge-3D graphene composite propose it as a promising electrode in high-performance thin film LIBs.

Nanostructured ternary Al-Mg-B films possess high hardness and corrosion resistance. In the present work, we study their electronic structure and electrical transport. The films exhibit semiconducting characteristics with an indirect optical-bandgap of 0.50 eV, as deduced from the Tauc plots, and a semiconductor behavior with a Fermi level of ∼0.24 eV below the conduction band. Four-probe and Hall measurements indicated a high electrical conductivity and p-type carrier mobility, suggesting that the electrical transport is mainly due to hole conduction. Their electrical properties are explained in terms of the film nanocomposite microstructure consisting of an amorphous B-rich matrix containing AlMgB14 nanoparticles.

Surface doping can be a powerful way to modify the electronic properties of graphene with the unique potential to retain the excellent pristine properties of graphene. Here, we report an atomic surface doping method for graphene via dissociation of adsorbed precursor molecules of tetrafluorotetracyanoquinodimethane (F4-TCNQ) induced by hydrogen plasma treatment. Significantly, the location of the dopant N atoms can be pre-determined by the location and orientation of the F4-TCNQ molecule precursor on graphene, leading in principle to site-selective doping. Furthermore, the molecular precursor is stable under ambient conditions, satisfying an important consideration for patterning processes.

The effects of growth temperature on the microstructure evolution and electrical transport properties of Cu2O films were investigated. Nanocrystalline Cu2O films with modest p-type semiconducting properties (Hall mobilities ∼20 cm2/Vs, hole concentrations ∼1016 cm−3) were successfully prepared at room temperature without post-annealing. Bottom gate and top contact p-channel Cu2O thin-film transistors (TFTs) were constructed on flexible polyethylene terephthalate substrates at room temperature, which shows superior transfer performance (field effect mobility ∼2.40 cm2/Vs and current on/off ratio ∼3.96 × 104). The low processing temperature and the good electrical performance of the p-type Cu2O TFTs suggest their good potential for applications in high-throughput and low-cost electronics.

Microwave plasmas were employed to synthesize single- or double-layer graphene sheets on copper foils using a solid carbon source, polymethylmetacrylate. The utilization of reactive plasmas enables the graphene growth at reduced temperatures as compared to conventional thermal chemical vapor deposition processes. The effects of substrate temperature on graphene quality were studied based on Raman analysis, and a reduction of defects at elevated temperature was observed. Moreover, a facile approach to incorporate nitrogen into graphene by plasma treatment in a nitrogen/hydrogen gas mixture was demonstrated, and most of the nitrogen atoms were verified to be pyridinelike in carbon network.

We study the solar power conversion efficiency in hybrid solar cells based on zinc oxide (ZnO)/antimony trisulfide (Sb2S3)/poly-3(hexylthiophene) heterojunctions. The incorporation of ZnO nanowire arrays (NAs) structure results in power conversion efficiency of 2.9%, or 20% higher than the control device. Absorption spectra and numerical simulation analysis provide strong evidence revealing that the enhanced performance is mainly induced by (1) enhanced optical absorption from light-trapping effect of NAs and (2) reduced bulk recombination rate in Sb2S3 from shortened electron injection pathway into ZnO. Significantly, numerical simulations show that the expected interface recombination increase from larger interfacial area effects is negligible.

The electronic band structure and p‐type conductivity of CuAlO2 films were modified via synergistic effects of energy band offset and partial substitution of less‐dispersive Cu+ 3d10 with Cu2+ 3d9 orbitals in the valence band maximum by alloying nonisovalent Cu‐O with CuAlO2 host. The Cu‐O/CuAlO2 alloying films show excellent electronic properties with tunable wide direct bandgaps (∼3.46–3.87 eV); Hall measurements verify the highest hole mobilities (∼11.3–39.5 cm2/Vs) achieved thus far for CuAlO2 thin films and crystals. Top‐gate thin film transistors constructed on p‐CuAlO2 films were presented, and the devices showed pronounced performance with Ion/Ioff of ∼8.0 × 102 and field effect mobility of 0.97 cm2/Vs.

Fluorophore-functionalized cubic boron nitride (cBN) films grown by chemical vapor deposition were achieved by immobilizing rhodamine B isothiocyanate onto their surfaces. To perform the immobilization, the cBN substrates were modified with amino groups by photochemical reaction between hydrogen-terminated cBN surfaces and allylamine. The surface analysis of hydrogen-terminated cBN films surfaces and after functionalization with x-ray photoelectron spectroscopy verified that rhodamine B was indeed attached to the cBN surfaces with covalent bonding. The rhodamine B-functionalized cBN surfaces showed significant variation in fluorescent spectra and confocal imaging upon the treatment in acidic or basic solutions.

The composition dependence of phase transition temperature in (1-x)PbSc1/2 Ta 1/2O3-xPbHfO3 (PSTH) ceramics ( 0 ≤ x ≤ 0 . 2 ) has been investigated by Raman spectra. From the typical phonon mode variations, the PSTH ceramics unambiguously undergoes three structural transformations with increasing the temperature from 82 to 673 K. It was found that the F 2 g phonon mode disappears above the Curie temperature. Moreover, the PSTH ceramics exhibited the paraelectric to ferroelectric phase transitions at 287, 293, 313, 320, and 330 K with the composition. The phenomena can be ascribed to the enhanced length of Pb-O-Ta bonds induced by the incorporation of Hf4+ ions.

p-type conductivity in intrinsic silicon nanowires (SiNWs) synthesized by an etching method was achieved via surface coating of MoO3 and tetrafluoro-tetracyanoquinodimethane thin layers. Characterization of field-effect transistors fabricated from single SiNW revealed a decrease in resistivity by six orders of magnitude and an increase in hole concentration by eight orders of magnitude with respect to the original silicon wafers. The enhancement of p-type conduction was demonstrated to originate from the interface charge transfer between inorganic/inorganic and organic/inorganic heterojunctions and the enrichment of hole concentration in SiNW surfaces based on band energy alignment and x-ray photoelectron spectroscopic analysis.

We report the mild hydrothermal synthesis of single-crystalline rutile TiO2 nanorod arrays (NRAs). The method reported here shows great versatility and can be used to grow TiO2 NRAs on a large diversity of substrates including Si, Si/SiO2, sapphire, Si pillars, and fluorine doped tin oxide (FTO)-covered glass. The average diameter and length of the nanorods prepared at typical conditions are ∼60 nm and 400 nm, respectively. Dye-sensitized solar cells assembled with the TiO2 NRAs grown on the FTO-covered glass as photoanode were prepared with a photoconversion efficiency of ∼1.10%.

n-ZnO/p-GaN heterojunction light-emitting diodes with and without a sandwiched AlN layer were fabricated. The electroluminescence (EL) spectrum acquired from the n-ZnO/p-GaN displays broad emission at 650 nm originating from ZnO and weak emission at 440 nm from GaN, whereas the n-ZnO/AlN/p-GaN exhibits strong violet emission at 405 nm from ZnO without GaN emission. The EL intensity is greatly enhanced by inserting a thin AlN intermediate layer and it can be attributed to the suppressed formation of the GaOx interfacial layer and confinement effect rendered by the AlN potential barrier layer.

We demonstrated a simple and low-cost fabrication of ZnO p-n homojunction. The junction consists of n-type ZnO nanowires array by a hydrothermal method covered with p-type Al, N co-doped ZnO film by a sol-gel method. The junction exhibits good rectification characteristics, with reverse leakage current and rectification ratio of ∼5 μA and ∼150 at bias of 3 V, respectively. The junction is operated as a photodetector when light radiation is shined on the glass-side of the device. The photodetector shows a peak responsivity at 384 nm with UV-visible responsivity ratio (R384 nm/R550 nm) of ∼70 at an operating bias of −3 V.

Crossbar heterojunction arrays of n-CdSe:In nanowires (NWs) and p-Si nanoribbons (NRs) were built by ac electrical field-directed assembly. The junctions showed significant rectifying characteristics. With the p-Si NRs as gates, the junctions function as junction field effect transistors (JFETs) with high stability and reproducibility in performance. A small variation in gate voltage from −2 to −1 V was demonstrated to manipulate the current in n-CdSe:In NW channels by a factor near 103. The JFETs also showed a subthreshold swing value (67 mV/dec) approaching the theoretical limit (60 mV/dec), suggesting the great application potentials of the junctions in integrated nanoelectronics.

p-type conduction in hexagonal boron nitride (hBN) films was achieved by beryllium implantation and subsequent rapid thermal annealing treatment. The dependence of phase composition and electrical properties of hBN films on the implantation fluence and annealing was studied. A maximum resistivity reduction by six orders of magnitude was demonstrated. Hall measurements revealed a corresponding hole concentration of 3×1019 cm−3 and mobility of 27 cm2/V s. The activation energy of Be ions was estimated to be 0.21 eV. It is suggested that hBN is a promising wide bandgap semiconductor for applications in high-temperature electronic devices and transparent conductive coatings.

A convenient nanotechnique is reported to tailor the light emission properties of organic emitter poly[2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylene vinylene] (MEH-PPV) by coupling to resonance-tuned silver nanoantenna arrays. It is revealed experimentally and theoretically that the enhanced photoluminescence from the MEH-PPV/silver nanoantenna complex may originate from the energy transfer effect in the surface plasmon resonance coupling between the MEH-PPV and silver nanocaps and from local electromagnetic field enhancement of nanogaps between the silver nanocaps in the background of the light-emitting MEH-PPV. The results are corroborated by the finite difference time domain simulation results.

High-sensitivity detection of toxic heavy metal cations such as Hg2+ and Cd2+ ions was demonstrated using single silicon nanowire field-effect transistors (SiNW-FETs). The conduct-ance of FET fabricated from thermally oxidized SiNWs functionalized with 3-mercaptopropyltriethoxysilane showed high sensitivity to Hg2+ and Cd2+ ions at a concentration down to 10−7 and 10−4M, respectively. Linear relationship between the logarithmic concentration of metal ions and the current change was observed. The SiNW sensor could be recycled to regain nearly the same sensitivity. Comparative experiments showed that SiNW-FET sensors have great selectivity for detecting Hg2+ and Cd2+ over other metal cations.

Cubic boron nitride (cBN) film-based sensors for detecting Hg2+ ions were developed by surface functionalization with dansyl chloride. To immobilize dansyl chloride, 3-aminopropyltriethoxy silane was modified on hydroxylated cBN surfaces to form an amino-group-terminated self-assembled monolayer. The covalent attachment of the amino groups was confirmed by x-ray photoelectron spectroscopy. The selectivity and sensitivity of the sensors to detect diverse metal cations in ethanol solutions were studied by using fluorescence spectroscopy, revealing a great selectivity to Hg2+ ions. Significantly, the dansyl-chloride-functionalized cBN film sensors were recyclable after the sensing test.

We report the fabrication of fully transparent and flexible nanowire transistors by combining a high-quality In2O3:Zn nanowire channel, a SiNx high-κ dielectric, and conducting Sn-doped In2O3 electrodes on a polyethylene terephthalate substrate. The devices show excellent operating characteristics with high carrier mobilities up to 631 cm2 V−1 s−1, a drain-source current on/off modulation ratio ∼1×106, a high on-state current ∼1×10−5 A, a small subthreshold gate voltage swing of 120 mV decade−1, and a near zero threshold voltage. The devices further show high reproducibility and stable performance under bending condition. The high-performance nanowire transistors would enable application opportunities in flexible and transparent electronics.

Control and utilization of hysteresis in nanodevices is an important issue. In this paper, we show an enormous hysteresis in zinc-doped In2O3 nanowire field-effect transistors. Various measurements including changing the operating atmosphere, ozone treatment, and surface passivation were performed to understand and control the hysteresis. The hysteresis could be readily controlled by modifying the nanowire surface. Utilizing the hysteresis, the as-fabricated devices can function as nonvolatile memory elements with high charge storage stability exceeding 4 h. We propose that chemical species such as water molecules adsorbed on the devices and surface oxygen defects in the amorphous layer mainly originated from Zn2+ substitution of In3+ are the main causes of the large hysteresis and the nonvolatile memory effect.

Large-area, wafer-scale silicon nanowire arrays prepared by metal-induced chemical etching are shown as promising scalable anode materials for rechargeable lithium battery. In addition to being low cost, large area, and easy to prepare, the electroless-etched silicon nanowires (SiNWs) have good conductivity and nanometer-scale rough surfaces; both features facilitate charge transport and insertion/extraction of Li ions. The electroless-etched SiNWs anode showed larger charge capacity and longer cycling stability than the conventional planar-polished Si wafer.

Substrate temperature and chemical etching were demonstrated to be dominant factors in determining the in-plane orientation of AlN films grown epitaxially on SrTiO3 (STO) (111) substrates by magnetron sputtering. Single-domain epitaxial AlN films were grown at moderate temperatures of 270–370°C with a sharp interface and orientation relationship of [21¯1¯0]AlN∥[01¯1]STO and (0002)AlN∥(111)STO. At temperature above 470°C, an additional 30° in-plane-rotated AlN domain appeared, and increased in percentage with increasing temperature. A model based on the reconstruction of STO (111) surfaces from (1×1) to (3×3)R30° was proposed to account for the formation of this new domain.

Surface functionalization and modification scheme of cubic boron nitride (cBN) films deposited by chemical vapor deposition was demonstrated. A homogeneous layer of amino groups was bonded covalently on the B and/or N atoms of cBN surface via a photochemical reaction with allylamine. X-ray photoelectron spectroscopy was carried out to verify comprehensively each stage of the surface modification process. Gold nanoparticles (AuNPs) were self-assembled on the amine-terminated cBN surface, and a dense and well-distributed AuNPs monolayer was obtained. Modification of amine-terminated cBN films with amine-modified DNA probes presents an example of applications as DNA biosensors.

Zn-doped In2O3 nanowires (NWs) were prepared by simple chemical vapor deposition and were systematically characterized. Field-effect transistors (FETs) constructed from the Zn-doped In2O3 nanowires exhibit excellent performance characteristics such as high mobility, “high-on-state” current of 105A and large on/off current ratio of 107. Single-NW-FETs can successfully drive an organic light-emitting diode, revealing the application potential of Zn-doped In2O3 NW-FETs in high-performance displays.

P-type conductivity of polycrystalline cubic boron nitride (cBN) films was achieved by implantation of beryllium ions. The effects of implantation doses and annealing on the phase composition and electrical properties of cBN films were studied. A reduction in resistivity by seven orders of magnitude was observed. Hall measurement revealed a corresponding hole concentration of 6.1×1018cm−3 and mobility of 3cm2∕Vs. The activation energy was estimated to be 0.20±0.02eV from the temperature dependence of resistance. The electrical properties of Be-implanted films are comparable to that of Be-doped cBN single crystals synthesized by high-pressure and high-temperature method.

High-density, uniform diamond nanopillar arrays were fabricated by employing bias-assisted reactive ion etching in a hydrogen/argon plasma. Gold nanodots were employed as etching masks. The formation of nanopillar structure is associated with the directional physical etching/sputtering by ion bombardment and selective chemical etching of sp2 carbons by reactive hydrogen atoms and ions. The density and geometry of the nanopillars depend on the initial structure of diamond films and reactive ion etching conditions. The nanopillars with high aspect ratio and large surface area may have potential applications in high-efficiency and high-sensitivity diamond-based biomedical and chemical sensors and in mechanical and thermal management.

Single crystal AlN thin films were epitaxially grown on GaN/sapphire (0001) substrates on a macroscopic scale by magnetron sputtering. The microscopic structure and orientation degree of the AlN epilayers were studied by high-resolution transmission electron microscopy, high-resolution x-ray diffraction, and reciprocal spacing mapping. It was revealed that the AlN epilayers have high in-plane and out-of-plane orientation degrees and low defect density. The electrical and optical properties of the AlN epilayers were also studied, and the results suggest that the AlN epilayers grown by sputtering may be employed in the fabrication of GaN-based light-emitting diode devices with increased efficiency.

Nanocubic boron nitride/nanodiamond (N-cBN/ND) multilayer structures with each alternating layer being ∼100nm thick have been prepared by magnetron sputter and microwave plasma enhanced chemical vapor depositions. These multilayers exhibit remarkable properties, in particular, the mechanical properties. The multilayer structure is characteristic with (i) extreme hardness (82GPa) considerably surpassing the values of the individual materials from which the multilayer is composed, (ii) high surface smoothness, (iii) significantly reduced film stress when compared with a single cBN layer of equivalent thickness, and (iv) great chemical stability. The N-cBN/ND multilayers developed have therefore important implications in mechanical and chemically resistant applications.

The microstructure, in particular, the surface and interface regions, of the c-axis orientated AlN films deposited on Si (100) substrates was studied. The films showed an evolutionary columnar growth process. In contrast to the previous reports, high-resolution transmission electron microscopy revealed that the AlN films grew directly on substrates without an amorphous interlayer, despite the large lattice mismatch between AlN and Si. The occurrence of misoriented and/or amorphous top layer suggested a subsurface growth/relaxation process of the AlN films by reactive sputtering.

The transport properties of single-crystal CdS nanoribbons were studied by evaluating the characteristics of field-effect transistors made of individual CdS nanoribbons. The nanoribbon transistors exhibited typical normally off n-channel characteristics with an on-off ratio as high as 104 in dark and in air. A barrier of 0.55eV at the metal-semiconductor contact was deduced from the temperature-dependent conductance. The CdS nanoribbons were highly sensitive to visible light and to adsorbed oxygen molecules. The transistor showed substantial improvement in performance under light irradiation and in vacuum.

Field-effect transistors made of individual CdSe nanoribbons were fabricated and characterized. The CdSe nanoribbon showed n-type semiconducting characteristics, while the transistors revealed a threshold voltage of 20.9V, an on-off ratio >104, and an electron mobility of 9.6cm2∕Vs in the dark. CdSe nanoribbons showed high sensitivity to above-band-gap irradiation with four-orders-of-magnitude increase in conductance and millisecond response speed. The increase of electron mobility due to light irradiation was demonstrated to contribute to increased photoconductance.

Cubic boron nitride (BN) films with improved crystallinity are deposited by physical vapor deposition at an extremely low substrate bias (−35V). The films are characterized by UV Raman in association with Fourier transformed infrared (FTIR) spectroscopy. The influences of bias voltage and film thickness on the characterizations are investigated. UV Raman, in contrast to FTIR, is demonstrated to be a more powerful tool with high sensitivity for quantitative and/or qualitative evaluation of the phase purity and crystallinity, especially as the film thickness increases. Hexagonal BN inclusions (less than 1%), not evident in FTIR, are clearly revealed by UV Raman analysis.

A simple coating technique was introduced to preserve the surface structure of samples for transmission electron microscopy (TEM) characterization, and used to study boron nitride (BN) films. A gold film precoated on the surface of BN films served to protect the BN surface against ion damages during sample preparation, and to separate and distinguish the film surface structure from the TEM glue. The technique enabled the observation of detailed surface microstructures of cubic BN (cBN) films, which provided direct evidences for understanding cBN growth mechanisms. The TEM sample technique is expected to be generally applicable to other film systems, particularly those with an amorphous topmost layer.

Well-aligned, ferromagnetic FePt nanorods have been fabricated by electron beam-induced deposition using an ultrahigh-vacuum scanning electron microscope. A mixture gas of iron pentacarbonyl and cyclopentadienylplatinum (IV) trimethyl was used as a precursor and post-annealing at 600 °C for 2 h was performed to accomplish the crystallization process. Each nanorod was composed of a chain of crystalline Fe-Pt alloy nanoparticles encapsulated within a carbon-containing sheath. The nanoparticles were identified to be face centered tetragonal (fct) FePt phase (L10,P4∕mmm) by electron diffraction and high-resolution transmission electron microscopy (HRTEM). The residual magnetic flux density Br of the nanorods was evaluated to be about 1.53 T via off-axis electron holography, showing a strong ferromagnetic character.

We present an absolute measurement of a two‐photon absorption (TPA) coefficient of C60 thin film at 633 nm. Large values of β≊4.4 cm/W were determined. A nearly resonant TPA transition around the 3.76 eV absorption region was discussed.

The possibility of simultaneous multiple wavelength lasing in various neodymium host crystals such as Nd:YAG, Nd:YLF, Nd:BEL, and Nd:YAP has been analyzed by the ‘‘oscillation condition.’’ It is shown that this kind of laser can be realized in all the described crystals in pulsed state, but only achieved in the Nd:YAP crystal in continuous‐wave state. On the basis of the analyzed results, we have achieved cw simultaneous multiple wavelength lasing in Nd:YAP crystal for the first time at both 1.0795 and 1.3414 μm.