In-situ compensation

17 Electrical Characterization of Ferroelectric Properties in the Sub-Micrometer Scale 

Roelofs1, T. Schneller1, U. BOttger K. Szol2, andR. Waser2 

Institut fur Werkstoffe der Elektrotechnik, RWTH Aachen, Germany 

In the growing field of applications for ferroelectric thin films it is of great interest to investigate the ferroelectric properties on a nanometer scale. A powerful tool for the monitoring and 

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In all experiments, we start with an in situ compensation of the residual spectral phase of the IR pump pulse, introduced by dispersive elements in the pump beamline. By this means, we make sure to have BWL pulses in the experiment if the zero phase is applied to the SLM. The residual phase is found by adaptive optimization of the total photoelectron yield from multiphoton ionization of ground state Xe atoms, which are led effusively into the interaction region. It turned out to be sufficient to parameterize the trial phase by a fifth-order polynomial. In the... 

Figure 17.13 Comparison of mathematical and in-situ compensation, current response and hysteresis loop of stand-alone 300 nm x 300 nm PZT capacitor...

Such sensors utilizing solid-state electronics have significant advantages. The actual sensing area is very small. Hence, a single miniaturized solid-state chip could contain multiple gates and be used to sense several ions simultaneously. Other advantages include the in-situ impedance transformation and the ability for temperature and noise compensation. While the concept of the ISFET is very... 

Thus, as will be shown in this book, the effect of electrochemical promotion (EP), or NEMCA, or in situ controlled promotion (ICP), is due to an electrochemically induced and controlled migration (backspillover) of ions from the solid electrolyte onto the gas-exposed, that is, catalytically active, surface of metal electrodes. It is these ions which, accompanied by their compensating (screening) charge in the metal, form an effective electrochemical double layer on the gas-exposed catalyst surface (Fig. 1.5), change its work function and affect the catalytic phenomena taking place there in a very pronounced, reversible, and controlled manner. 

Nitrile oxides are very reactive dipoles which, apart a few members, need to be prepared in situ for their tendency to dimerize to furoxans [86], This behaviour represents a limit to their use with alkylidenecyelopropanes that is only in part compensated by their reactivity. The cycloadditions of several nitrile oxides with alkylidenecyelopropanes were extensively studied in connection with the rearrangement process leading to dihydropyrid-4-ones 336 [64, 87],... 

The reaction conditions chosen for the in situ IR studies are often much milder (25-100 °C, 100 bar) than the process conditions (140 °C, 250 bar), which may not affect the equilibria, as the higher pressure compensates for the higher temperature. The relative rate, however, of isomerisation of 1-alkenes may increase dramatically between room temperature and 140 °C. 

A variation of in-situ volumetry (or manometry) is its combination with high temperature coulometry as shown in Figure 16-4. The A n( ) change in the gas volume due to the reaction is compensated for by a corresponding flux of ions across an appropriate solid electrolyte. This coulometric transport is potentiostatically controlled with a reference electrode (Fig. 16-4). Since 10 p A times 1 s = 10 pC corresponds to ca. 10-11 mol, the sensitivity of the combined volumetry-coulometry matches that of tensiometry. Limitations of this method are leaks and the small electronic transference in the electrolyte. 

Perhaps the most important new approach to chemical measurements has been the use of sensors for oceanic chemistry. Sensors comprise a transducer and its supporting electronic instrumentation. The key feature of sensors is their ability to monitor the concentration of a particular analyte continuously, so that the dimension of time can be added to the traditional three dimensions of spatial measurements. An example of a sensor is a pH electrode, coupled with a high-impedance voltmeter and a means of standardization and temperature compensation in situ. In principle, such a sensor can monitor pH continuously for days at a time while transferring the data to a recorder or memory device. One can contemplate towing an array of sensors at various depths simultaneously, obtaining three-dimen-o tin us d ta t. i Dr v e th two- imensional data a ail-... 

Commercial gel-filled pH probes were inserted into the soil column at 3 cm intervals, located between the anode and cathode (Figure 1). These were inserted through butyl rubber septa placed into holes drilled into the sides of the column. The pH probes were calibrated using standard buffer solutions before insertion into the soil column. Readings were taken daily for the duration of the experiment, by placing a reference electrode into a well at the top of the column, and connecting the reference and in-situ pH probes to an Orion Model EA 940 Expandable Ion Analyzer. All pH measurements were temperature compensated to 25 °C. 

Experimental proof of control of the mask temperature with the chiller in a Gen 2 OVPD module under process conditions (showerhead heated to 325 °C) was achieved by in situ temperature measurement, as shown in Fig. 9.4. The experiments were performed at atmospheric pressure and at a deposition pressure of 0.9 mbar typical for OVPD, and for chiller temperatures between 5 and 30 °C. The mask temperature can be linearly controlled by the chiller temperature. The observed AT of 6.5 degrees is in good agreement with modeling prediction of 3 degrees in Fig. 9.3. In addition, measurements during a typical OVPD deposition time of 2 to 6 min confirmed there is no temperature drift under process conditions over time. The data prove that heat conductance and radiation is perfectly compensated by the chiller capacity. 

Fig. 5.3 Schematic showing the changes in strain rate and elastic/creep strains of the individual constituents that occur during creep of a composite, (a) Strain rate versus time, (b) strain rate versus in situ stress acting in the fibers and matrix. In both plots, the shadowed portions show the elastic strain components, which compensate the creep rate mismatch of the individual phases, such that the total creep rates of the constituents remain equal. The creep mismatch ratio (CMR) is discussed in Section 5.2.4. After Wu and Holmes.31...

The use of laser Raman spectrometry in order to quantitatively investigate the urea synthesis under process conditions has been reported by Van Eck et al. (1983). Only Raman spectroscopy seems to suit the problem, since the visible radiation which is used to excite and detect Raman transitions can easily be directed to a measuring cell. Furthermore, water, which is an acceptable solvent, and all compounds involved in the synthesis show characteristic Raman bands. In order to compensate for many of the instrumental factors relative intensities were used instead of absolute intensities. Reproducible window mountings are a necessity. The effect of pressure and temperature on the Raman intensity have to be taken into account if measurements are to be carried out in situ (Sec. 6.8). The effect of the temperature is moderated by using an internal standard. 

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