Single-crystal polish

One of the main uses of these wet cells is to investigate surface electrochemistry [94, 95]. In these experiments, a single-crystal surface is prepared by UFIV teclmiqiies and then transferred into an electrochemical cell. An electrochemical reaction is then run and characterized using cyclic voltaimnetry, with the sample itself being one of the electrodes. In order to be sure that the electrochemical measurements all involved the same crystal face, for some experiments a single-crystal cube was actually oriented and polished on all six sides Following surface modification by electrochemistry, the sample is returned to UFIV for... 

Adsorbed molecules are more strongly held at the sites where the weakest metal-metal bonding is to be found, and these conespond to the active sites of Langmuir. A demonstration of this effect was found in smdies of the adsorption of H2S from a H2S/H2 mixture on a single crystal of copper of which die separate crystal faces had been polished and exposed to die gas. The formation of copper sulphide first occuiTed on die [100] and [110] planes at a lower H2S partial pressure dran on die more densely packed [111] face. Thus die metal atoms which are less strongly bonded to odrer metal atoms can bond more strongly to die adsorbed species from die gas phase. 

Later, Bi(OlT), Bi(2TT), Bi(001), and Bi(101) faces were stud-ied.28,152 253 254,705 The accuracy of the experimental results has been established by statistical analysis. A very slight variation in capacitance (3-6%) with v (from 60 to 21,000 Hz) was observed for electrochemically polished single-crystal Bi. Therefore, to a first approximation, the measured admittance was identified with the differential capacitance C. 

Can one use STM to study spillover/backspillover phenomena and to confirm the origin of electrochemical promotion The answer is positive and the experimental setup used for the first demonstration of electrochemically controlled spillover/backspillover between a catalyst-electrode (Pt) and a solid electrolyte (p"-Al203) is shown in Figure 5.48.78,79 A polished Pt(lll) single crystal (lOmmxlOmmxlmm) was mounted on an appropriately carved polycrystalline p"-Al203 sample (20mmx20mmx3mm). 

Fe, Re and Mo samples were typically of about 1 cm area by 0.5 mm thick and were spark cut from single crystal rods. These were subsequently polished using standard metallurgical techniques euid... 

Preparation of the Pt(lll) Single-Crystal Electrode. The Pt single-crystal electrode was prepared according to the procedure developed by Clavilier (7) and oriented using the methodology of Hamelin (8). It was subsequently polished with alumina to a mirror-like finish. The quahty of the Pt(l 11) surface was verified by recording CV... 

The authors acknowledge very helpful discussions with Dr. R. Adzic of the Institute of Electrochemistry, Belgrade, concerning the underpotential deposition of lead on single crystal silver substrates after chemical polishing. The authors also acknowledge support of the research by the U.S. Office of Naval Research. 

The platinum single crystals treated in this May are small spherical platinum beads Hith a diameter ranging from l.S to 1.9 am obtained by melting of a Mire. They are oriented, cut and polished according to the technique described in (10.) Mith an accuracy uithin 3 minutes of the nominal orientation. After polishing, the samples are annealed at 1300°-1500 C to eliminate the perturbed surface layer. 

The Ru single crystal was oriented by Laue x<-ray back-scattering to within 1° of the Ru(001) plane, cut by a diamond saw and mechanically polished. After being etched in hot aqua regia for about 15 min, the crystal was spot welded to two tantalum heating wires which were connected to two stainless steel electrodes on a sample manipulator. The temperature was monitored by a Pt/Pt-10% Rh thermocouple which was spot welded to the back of the crystal. 

In the early days of silicon device manufacturing the need for surfaces with a low defect density led to the development of CP solutions. Defect etchants were developed at the same time in order to study the crystal quality for different crystal growth processes. The improvement of the growth methods and the introduction of chemo-mechanical polishing methods led to defect-free single crystals with optically flat surfaces of superior electronic properties. This reduced the interest in CP and defect delineation. 

To obtain the three low index surfaces, a polishing jig shown in Fig. 2-8 was made. The jig should be such that the inner shaft should move smoothly in the vertical direction but shoiild not rattle in the shell. It is also required that the guide surface be perpendicular to the direction of the shaft motion. The single crystal was attached on the inner shaft by epoxy resin for orientating and polishing. To obtain either the (111) or (100) surface, the orientation of one of the facets was adjusted to be identical with the guide... 

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