No abstract

We report here the temperature-dependent measurements of the valence spectra, the C 1s and the Si 2p core level spectra of the one monolayer C 60 film adsorbed on Si͑001͒-(2ϫ1) and Si͑111͒-(7ϫ7) surfaces, using photoelectron spectroscopy. At 300 K, most C 60 molecules are physisorbed with the coexistence of minority chemisorbed species on both Si͑001͒-(2ϫ1) and Si͑111͒-(7ϫ7) surfaces. After annealing the samples at 670 K, C 60 molecules change the bonding nature to a chemisorption that has both covalent and ionic characters. The covalent bonding orbital is observed at a binding energy of 2.10 eV on both Si surfaces. The amount of charge transfer is estimated to be 0.19 electrons per C 60 molecule on the Si͑001͒ surface, and to be 0.21 electrons per molecule on the Si͑111͒ surface. We consider the origin of the change in bonding nature to the different distance between two dangling bonds that results from the rearrangement of the surface Si atoms. After annealing at 1070 K, C 60 molecules decompose and the SiC formation takes progress at the interface. On the Si͑001͒ surface, the molecular orbitals ͑MO's͒ disappear at 1120 K and the binding energies of peaks observed in the valence spectra indicate the formation of SiC islands at this temperature. On the Si͑111͒ surface, the disappearance of MO's and the formation of SiC islands are verified at 1170 K. The difference in formation temperature is attributed to the different surface structure. ͓S0163-1829͑99͒00328-8͔

No abstract

No abstract

SUMMARYA quartz crystal microbalance (QCM) sensor coated with a sensing film has been studied as a gas-sensing device with high gas selectivity and high sensor sensitivity. One of the problems to be solved for practical applications is that the resonant frequency of a QCM sensor drifts due to the influence of humidity. We investigated a method for compensating the humidity drift of a QCM sensor for NH 3 gas by using an element coated with a reference film that was prepared by modifying the phosphate group of zirconium phosphate in the sensing film with sodium hydroxide. The response characteristics of the reference element were measured. The results showed good agreement with the humidity response of the sensor element when not responding to ammonia gas. It was found that compensation of the humidity drift was successfully accomplished by calculating the frequency difference between the sensor element and the reference element. An application to small QCM (1.3 × 0.9 mm) is also presented. C⃝ 2015 Wiley Periodicals, Inc. Electron Comm Jpn, 98(6): 1-7, 2015; Published online in Wiley Online Library (wileyonlinelibrary.com).