Measurement in vacuum

A. Berman, Total Pressure Measurements in Vacuum Technology, Academic Press, Inc., Orlando, Fla., 1985, pp. 140—146. 

Fig. 53. Current-voltage curves measured in vacuum at RT on M-DNA (open circles) and B-DNA (closed circles). The former indicates semiconductor-like behavior and the latter metal-like. Reproduced with permission from Ref. (178). Copyright 2001, American Physics Society.

Partial pressure measurement in vacuum technology , Balzers A. G. (ed.) Liechtenstein. 

J.H. Leek Pressure measurements in vacuum systems, Chapman Hall, London (1964)... 

Adjustable Conductivity Electrodes for Measurements in Vacuum and Controlled Atmospheres, P.H. Plesch, Chemistry and Industry, 1973, 699-700. 

The pressures measured in vacuum technology today cover a range from 1013 mbar to 10 mbar, i.e. over 15 orders of magnitude. The enormous dynamics involved here can be shown through an analogy analysis of vacuum pressure measurement and length measurement, as depicted in Table 3.1. 

Vapour and Gas Measurements in Vacuum with the Quartz Crystal Microbalance... 

The characteristic orange light produced by sodium in a flame is due to an intense emission called the sodium D line. This line" is actually a doublet, with wavelengths (measured in vacuum) of 589.157 88 and 589.755 37 nm. The index of refraction of air at a... 

The life times of EPR signal with cycles of light-off and -on were measured in vacuum and in 30 Torr of He and N2.n) In vacuum, a small signal (g=2.020,... 

Cryogenic level measurement in vacuum-insulated tank. 

The procedure for the THG measurements of thin films needs less steps. As the thin films can be directly measured in vacuum, the calibration of the air contribution is not required. Furthermore, the film substrate is usually fused silica that makes also the initial calibration of the THG setup with a fused silica plate superfluous. However, the film thickness and its refractive index have to be determined prior to the THG analysis. 

Fig. 6.12. Simulated (lines) and experimental (symbols) transfer characteristics (measured in vacuum at Vds —1 V), of as fabricated TC pentacene TFTs for three different temperatures 300 K (squares), 240 K (circles), 205 K (triangles) (L = 100 pm, W = 200 pm, dox = 60 nm) [154].

It is reasonable to ask how accurately the mass sensitivity in vacuum reflects the sensitivity when the device has liquid contacting the surface. This was investigated by monitoring the frequency shift of a single device both during vacuum deposition of a metal film and removal of the same film in an etching solution. The sensitivity in the liquid was approximately 6% less than the value measured in vacuum, a discrepancy that lies within our estimates of experimental uncertainty in this case [54]. 

J. H. Leck, Pressure Measurement in Vacuum Systems, Chapman and Hail, London, 1964. 

The difference in etch rate between (111) and (100) surfaces was related to the bond densities on the two surfaces in the early surface kinetics models. According to Hesketh et the etch rate difference between (100) and (111) planes is due to the difference in the surface free energy of the crystal planes which is proportional to the number of bonds on the surface. The (111) plane, which has the lowest surface free energy measured in vacuum, has the lowest bond density and thus has the lowest etch rate. They postulated that the etch rate of crystal planes is a function of the total number of bonds at the surface, that is, the sum of the in-plane, lateral bonds between atoms in the plane of the surface, and surface bonds, dangling bonds. It was recognized however, that this effect alone will not cause etch rate differences of more than a factor of two. ° ... 

Furthermore, Li- and Ca/Cu(TCNQ)Cu devices were fabricated and measured in vacuum to avoid oxidation because of their high reactivity. A Cu/Cu(TCNQ) substrate was placed into a substrate holder with two contact pins. The substrate was covered with a shadow mask that exposed only a part of the Cu stripe... 

If a heat transfer field is two-dimensional and the variation in the index of refraction only occurs perpendicular to the light beam direction, the fringe shift or difference in the optical path length (measured in vacuum wavelength) e can be expressed as... 

A small packing density causes a reduction of the film refractive index, the refractive index of a porous film measured in vacuum is therefore low. On exposure to the atmosphere, however, a markedly increased value due to the sorption of water vapour, with n i0 = 1.33, is observed especially in the case of films of low refracting... 

Positron annihilation lifetime spectra of MCM-41 and zeolite Y were measured in vacuum and air. For MCM-41 a very long positron lifetime component could be observed not only in vacuum, but also in air, while for zeolite Y it can only be observed in vacuum with a weak intensity. These peculiar positron annihilation characteristics were explained by air quenching mechanism of o-Ps annihilation in MCM-41. For comparison, positron annihilation lifetime spectra of MCM-41 were also measured in different O2 and N2 level. The results show that oxygen is more effective in quenching than nitrogen because of its spin unpaired electron. 

If these corrections are neglected, the difference between the In A parameters measured in vacuum and in a foreign gas would constitute at 1,000 K about 1.25, and between the E parameters, approximately 10.4 kJ moP The majority of researchers using the Arrhenius plot method fail to take these corrections into account, although the final figures for the E parameter are given frequently (see, e.g., [8]) to within a few kJ moP, or even a few tenths of kJ moP and the values of InA, to within an uncertainty of a few tenths of percent. 

The accuracy with which the mass sensitivity in vacuo reflects that when the device Is In contact with liquid was Investigated with an etching experiment. After evaporating an 80.5 nm-thick silver film onto Device 3, it was incorporated in an oscillator circuit and an open cell on the device surface was filled with 1.0 ml of water. After stable oscillation of the n - 1 mode was achieved, 0.1 ml of a 2 2 1 H20 H2S0 HN03 etchant was added to the cell. The 1470 ppm frequency shift measured as the film dissolved over a 15 min period yields a mass sensitivity of 17.4 cm /g, approximately 6% less than the value measured In vacuum. 

ESR spectra were measured for the samples oxidized to different extents and annealed under a high vacuum of 10 torr at various temperatures up to 1000 C. The spectra were first measured in vacuum and then after the exposure to air at room temperature. The siloxene sample annealed at temperatures above 400 C in vacuum showed ESR spectra over about 20 G, as shown in Figures 15-13 and 15-14 for the samples oxidized in water for 24 and 72 h, respectively. 

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