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In this work, a co-culture system with liver cancer cell line HepG2 and normal cell line L02 is used to investigate the selective effect on cancer and normal cells by plasma activated medium (PAM), which is closer to the real environment where cancer cells develop. Besides, the co-culture system is a better model to study the selective effect than the widely used separate culture systems, where the cancer cell line and normal cell line are cultured independently. By using the co-culture system, it is found that there is an optimum dose of PAM to induce significant cancer cell apoptosis while keeping minimum damage to normal cells. [ABSTRACT FROM AUTHOR]

The growth of diamond cubic Sn(x)Ge(1-x) alloy films via solid phase epitaxy from amorphous Sn(x)Ge(1-x) layers was investigated via transmission electron microscopy. The results showed that solid phase epitaxy with tin compositions of less than x=0.05 produced substitutional, strain relieved films that exhibit no phase separation. However, phase separation occurred in alloys with higher tin fractions.

We have performed the study on the dependence of laser beam induced current (LBIC) spectra on the temperature for the vacancy-doped molecular beam epitaxy grown Hg1-xCdxTe (x = 0.31) photodiodes by both experiment and numerical simulations. It is found that the measured LBIC signal has different distributions for different temperature extents. The LBIC profile tends to be more asymmetric with increasing temperature below 170 K. But the LBIC profile becomes more symmetric with increasing temperature above 170 K. Based on a localized leakage model, it is indicated that the localized junction leakage can lead to asymmetric LBIC signal, in good agreement with the experimental data. The reason is that the trap-assisted tunneling current is the dominant leakage current at the cryogenic temperature below 170 K while the diffusion current component becomes dominant above the temperature of 170 K. The results are helpful for us to better clarify the mechanism of the dependence of LBIC spectra on temperature for the applications of HgCdTe infrared photodiodes. [ABSTRACT FROM AUTHOR]

GaN films with single-crystal and polycrystalline structure were deposited on (111) and (100) MgAl2O4 substrates by metalorganic chemical vapor deposition using a substrate modified by chemical etching and thermal passivation. The interface structure and chemical bonding state of the GaN/MgAl2O4 interface was investigated using angle-resolved x-ray photoelectron spectroscopy and resulting valence band spectra. Our results indicate that the Al2O3 buffered layer induced by thermal passivation of the (111) substrate remains unchanged during GaN deposition, which is primarily responsible for the epitaxial growth of GaN on (111) MgAl2O4 substrate. However, for the as-processed (100) substrate, interfacial reactions take place between the formed MgO-terminated surface and GaN films and GaN with a polycrystalline structure on (100) substrate forms. From the interface engineering viewpoint, the appropriate interface modification will allow control of the interface reaction to obtain high-quality GaN films for future optoelectronic devices. [ABSTRACT FROM AUTHOR]

Thickness-modulated optical dielectric constants and band alignments of HfOxNy films grown by sputtering have been investigated by spectroscopic ellipsometry (SE) and x-ray photoelectron spectroscopy. Based on SE measurements, it has been noted that an increase in optical dielectric constant and band gap has been observed as a function of the film thickness. Analyses of thickness-dependent band alignment of the HfOxNy/Si system indicate that the valence band offset increases, but only slight change in the conduction band offset, resulting from the thickness-induced change in the structure. The suitable optical dielectric constants and band offsets relative to Si make sputtering-derived HfOxNy film a promising candidate for high-k gate dielectrics. [ABSTRACT FROM AUTHOR]

Composition-dependent electronic structure and optical properties of Hf1-xSixOy (0.1≤x≤0.6) gate dielectrics on Si at 450 °C grown by UV-photo-induced chemical vapor deposition (UV-CVD) have been investigated via x-ray photoemission spectroscopy and spectroscopy ellipsometry (SE). By means of the chemical shifts in the Hf 4f, Si 2p, and O 1s spectra, the Hf–O–Si bondings in the as-deposited films have been confirmed. Analyses of composition-dependent band alignment of Hf1-xSixOy/Si gate stacks have shown that the valence band (VB) offset (ΔEv) demonstrates little change; however, the values of conduction band offset (ΔEc) increase with the increase in the silicon atomic composition, resulting from the increase in the separation between oxygen 2p orbital VB state and antibonding d states intermixed of Hf and Si. Analysis by SE, based on the Tauc–Lorentz model, has indicated that decreases in the optical dielectric constant and increase in band gap have been observed as a function of silicon contents. Changes in the complex dielectric functions and band gap Eg related to the silicon concentration in the films are discussed systematically. From the band offset and band gap viewpoint, these results suggest that Hf1-xSixOy films provide sufficient tunneling barriers for electrons and holes, making them promising candidates as alternative gate dielectrics. [ABSTRACT FROM AUTHOR]

High-k gate dielectric YOxNy films were prepared by reactive sputtering. The effects of postdeposition annealing on the structure and optical properties of YOxNy films have been investigated. The x-ray diffraction result shows that the crystallization starts at the annealing temperature of 500 °C. Spectroscopic ellipsometry was employed to determine the optical properties of a set of YOxNy films annealed at various temperatures. It was found that the refractive index (n) of YOxNy films decreased with the increase of annealing temperature below 600 °C, whereas it increased with increasing annealing temperature above 600 °C. The annealing-temperature dependence of the optical band gap of YOxNy films was also discussed in detail. It has indicated that the optical band gap of YOxNy films shifts to higher energy after higher temperature annealing, which is likely due to the reduction of N content and the change of crystalline structure in YOxNy films. [ABSTRACT FROM AUTHOR]

N-doped ZnO films were prepared by annealing zinc oxynitride films deposited by rf reactive sputtering. Two Raman peaks were observed at 274 and 580 cm-1. According to the variation of the integral intensity of these two peaks, the nitrogen activation at 500 °C [the activation temperature (AT)] has been obtained. Below the AT, the integral intensities of them show a different variation trend. X-ray photoelectron spectroscopy (XPS) indicates the N chemical state variation for them and finds the activated Zn-N bond. Further analyses by photoluminescence (PL) spectra and spectroscopic ellipsometry (SE) have been carried out. The activated sample exhibits a symmetric emission peak at 3.22 eV assigned to be the A0X emission at room temperature. SE investigation takes account of samples within the different temperature span divided by the AT. Different factors, such as nitrogen dopant (N)O and the nanocrystal growth, which affect the redshift of the absorption edges, have been discussed. [ABSTRACT FROM AUTHOR]

The structural stability and optical properties of ultrathin HfAlOx films grown by facing-target reactive sputtering, depending on the postannealing temperature, have been determined via x-ray photoelectron spectroscopy and spectroscopic ellipsometry (SE). By virtue of the chemical shifts of Hf4f, Al2p, and Si2p core-level spectra, it has been found that the structural stability of HfAlOx/Si system sustains up to 800 °C. However, the breaking of the Hf–Al–O bond and the phase separation take place drastically at the annealing temperature of 900 °C. In particular, the information of an interfacial Si–O–Si bond as the dominant reaction during the postannealing treatment has been observed, confirmed by Fourier transform infrared spectroscopy. Analysis by SE, based on the Tauc-Lorentz model, has indicated that increase in the refractive index and reduction in thickness has been observed as a function of annealing temperature, originating from the annealing-induced higher packing density. The change of the complex dielectric functions and bandgap Eg correlated with the annealing temperature are discussed in detail. [ABSTRACT FROM AUTHOR]

The microstructure and optical dielectric constants of HfOxNy thin films deposited by using radio frequency reactive magnetron sputtering have been investigated at various substrate temperatures. Fourier transform infrared spectroscopy spectra indicate that an interfacial layer has been formed between the Si substrate and the HfOxNy thin film during deposition. Spectroscopy ellipsometry (SE) results show that the substrate temperature has a strong effect on physical properties of HfOxNy thin films such as refractive index n and extinction coefficient k. Meanwhile, the optical dielectric functions of the films have determined using SE data and optical absorption properties of HfOxNy thin films deposited at different substrate temperatures have also been studied. [ABSTRACT FROM AUTHOR]

A high-k Hf-silicate interfacial layer grown by the solid phase reaction between sputtered metallic Hf films and an underlying SiO2/Si substrate through in situ vacuum annealing and subsequent thermal oxidation has been investigated. By means of the chemical shifts of Si 2p, Hf 4f, and O 1s core-level spectra determined by x-ray photoelectron spectroscopy (XPS), the formation of an interfacial Si-O-Si bond as the dominant reaction during in situ thermal oxidation of the Hf/SiO2/Si gate stack has been confirmed. In situ vacuum anneals without air exposure at 700 °C accelerates the interface reaction and results in the formation of Si-rich Hf-silicate interfacial layer. Analysis by Fourier transform infrared spectroscopy (FTIR) has indicated that vacuum annealed samples containing the silicate interface layer effectively suppresses the growth of the interfacial SiOx layer compared to unannealed samples during postdeposition annealing. [ABSTRACT FROM AUTHOR]

The kinetics of the glass transition and the crystallization behavior of Ti–Cu–Ni–Sn–M (M=Zr,Mo,Ta) glassy alloys were investigated by differential scanning calorimetry and x-ray diffraction. The glass-forming ability (GFA) of the glasses was analyzed in terms of the fragility concept and the width of the supercooled liquid region. The Ti-base glasses studied were found to have lower GFA than Zr, Pd, La, Fe, Mg-base bulk metallic glasses (BMGs), but to be comparative GFA to Ni- and Au-base BMGs. Higher Mo content or higher Ti–Ta content in the alloys lowers the GFA. The chemical complexity and multiphase crystallization requiring long-range atomic diffusion may contribute to the thermal stability of the supercooled liquid against crystallization. The products of crystallization of the glasses include bcc β-Ti(M) solid solution and Ti[sub 2]Ni and Ti[sub 2]Cu intermetallics. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The x-ray photoelectron spectroscopy technique is employed to explain the different interfacial, as well as the optical properties of the HfTiO thin films with different Ti concentrations. An increase in the Ti concentration is shown to lead to a significant reduction in the band gap of the thin films.

Spectroscopic ellipsometry (SE) and x-ray photoelectron spectroscopy are used for examining the thickness-modulated optical dielectric constants and band alignments of Hf[O.sub.x][N.sub.y] films grown by sputtering. The suitable optical dielectric constants and band offsets relative to Si have made sputtering-derived Hf[O.sub.x][N.sub.y] film a very good candidate for high-k gate dielectrics.

X-ray photoemission spectroscopy and spectroscopy ellipsometry (SE) are employed to study composition-dependent electronic structure and optical properties of [Hf.sub.1-x][Si.sub.x][O.sub.y] gate dielectrics on Si at 450 degree Celsius. The results suggested that the [Hf.sub.1-x][Si.sub.x][O.sub.y] film offer sufficient tunneling barriers for electrons and holes to apply them as potential candidates as alternative gate dielectrics.

The effects of postdeposition annealing on the structure and optical properties of high-k gate dielectric Y[O.sub.x][N.sub.y] films grown by reactive sputtering are examined. The results suggested that the optical band gap of Y[O.sub.x][N.sub.y] films shifts to higher energy after higher temperature annealing due to the reduction on N content and the change of crystalline structure in Y[O.sub.x][N.sub.y] films.

Provides information on a study that generated nonsynchronous change of temperature rise and thermal expansion in thin films using transient laser pulse. Experimental procedures; Results and discussion on the study; Conclusion.