Diamond-Like Carbon film from Liquid Gas on Metallic Substrates

Liquid gas was used to produce DLC films on Cu, Al and steel substrates by DC plasma technique. The absorption in IR reflectance indicates, grown films are DLC. By deconvolution of room temperature UV-visible spectra of the films grown at 50 mtorr and 200${}^\circ$C, in addition to the spectra lines reported for CL, PL, PLC and ESR, some new spectra lines were obtained. We also, have seen exciton absorption line at room temperature.Comment: 6 pages, Postscript, 2 figure

Investigation of bias current and modulation frequency dependences of detectivity of YBCO TES and the effects of coating of Cu-C composite absorber layer

Bolometric response and noise characteristics of YBCO superconductor transition edge IR detectors with relatively sharp transition and its resulting detectivity are investigated both theoretically and experimentally. The magnitude of response of a fabricated device was obtained for different bias currents and modulation frequencies. Using the measured and calculated bolometric response and noise characteristics, we found and analyzed the device detectivity versus frequency for different bias currents. The detectivity versus chopping frequency of the device did not decrease following the response strongly, due to the decrease of the noise at higher frequencies up to 1 kHz, resulting in maximum detectivity around the modulation frequency of 100 Hz. We also improved the responsivity of the device through the increase of the surface absorption by using a novel infrared absorber, which is made of a copper-carbon composite, coated in a low-temperature process. Within the modulation frequency range studied in this paper, comparison of device detectivity before and after coating is also presented. © 2009 IEEE

Explanation of atomic displacement around lattice vacancies in diamond based on electron delocalization

The relationship between unpaired electron delocalization and nearest-neighbor atomic relaxations in the vacancies of diamond has been determined in order to understand the microscopic reason behind the neighboring atomic relaxation. The Density Functional Theory (DFT) cluster method is applied to calculate the single-electron wavefunction of the vacancy in different charge states. Depending on the charge and spin state of the vacancies, at outward relaxations, 84–90% of the unpaired electron densities are localized on the first neighboring atoms. The calculated spin localizations on the first neighboring atoms in the ground state of the negatively charged vacancy and in the spin quintet excited state of the neutral vacancy are in good agreement with Electron Paramagnetic Resonance (EPR) measurements. The calculated spin localization of the positively charged vacancy contrasts with the tentative assignment of the NIRIM-3 EPR signal to this center in (p-type) semiconductor diamond. The sign of the lattice relaxation in the diamond vacancy is explained based on the effect of electron delocalization on nearest-neighbor ion-ion screening, and also its effect on the bond length of neighboring atoms