Si lll

Recent XPS studies of interfaces have been performed on U/Si(lll)-7 x 7 face... 

A. Daniluk, P. Mazurek, K. Paprocki, P. Mikolajczak. RHEED intensity oscillations observed during the growth of YSi2 t on Si(lll) substrates. Surf SciSQl 226, 991. 

An interesting special application has been proposed by Schlichthorl and Peter.31,41 It aims at deconvolution of electrochemical impedance data to separate space charge and surface capacitance contributions. The method relies on detection of the conductivity change in the semiconductor associated with the depletion of majority carriers in the space charge region via potential-modulated microwave reflectivity measurements. The electrode samples were n-Si(lll) in contact with fluoride solution. 

Table 1 shows the kinetic data available for the (TMSjsSiH, which was chosen because the majority of radical reactions using silanes in organic synthesis deal with this particular silane (see Sections III and IV). Furthermore, the monohydride terminal surface of H-Si(lll) resembles (TMSjsSiH and shows similar reactivity for the organic modification of silicon surfaces (see Section V). Rate constants for the reaction of primary, secondary, and tertiary alkyl radicals with (TMSIsSiH are very similar in the range of temperatures that are useful for chemical transformations in the liquid phase. This is due to compensation of entropic and enthalpic effects through this series of alkyl radicals. Phenyl and fluorinated alkyl radicals show rate constants two to three orders of magnitude... 

The H-Si(lll) and H-Si(l 0 0)-2 x 1 have 2D rhombic and square lattices, respectively. Surface sites array in an isotropic style on H-Si(lll) but adopt the anisotropic distribution on H-Si(l 00)-2 x 1, these properties influence... 

Chidsey and coworkers made pioneering works in preparing covalently bonded monolayer films on silicon surfaces by the radical-initiated reaction of 1-alkenes with the H-Si(lll) surfaces. Reactions were carried out in neat deoxygenated alkenes using thermal decomposition of diacyl peroxides as the... 

Electrons from a scanning tunneling microscope (STM) in ultrahigh vacuum have been used to create surface-isolated silyl radicals on Si(lll), and their exposure to styrene leads to the formation of compact islands containing multiple... 

The functionalization of H-Si(lll) surface has been extended to the reaction with aldehydes. The reaction of H-Si(l 11) with octadecanal activated by irradiation with 150 W mercury vapor lamp (21 h at 20-50 °C) afforded a well-ordered... 

It has been observed that the H-Si(lll) and H -Si(lOO) surfaces develop a submonolayer oxide when exposed to an average sitting time of 1 h prior to gate oxidation in typical room air and room lighting conditions. Furthermore, the oxidation of the H-Si(lll) and H3.-Si(100) surfaces occurs when they are exposed to UV light in the presence of dry air or humid air. Analogous experiments are reported for the photo-oxidation of pSi. ... 

In this contribution it is shown that local density functional (LDF) theory accurately predicts structural and electronic properties of metallic systems (such as W and its (001) surface) and covalently bonded systems (such as graphite and the ethylene and fluorine molecules). Furthermore, electron density related quantities such as the spin density compare excellently with experiment as illustrated for the di-phenyl-picryl-hydrazyl (DPPH) radical. Finally, the capabilities of this approach are demonstrated for the bonding of Cu and Ag on a Si(lll) surface as related to their catalytic activities. Thus, LDF theory provides a unified approach to the electronic structures of metals, covalendy bonded molecules, as well as semiconductor surfaces. 

Cu and Ag on Si(lll) surfaces. In the last example, we come back to surfaces. It is well known (44-46) that Cu catalyzes the formation of dimethyl-dichlorosilane from methylchloride and solid silicon, which is a crucial technological step in the synthesis of silicone polymers. Even today, the details of the catalytic mechanism are unclear. Cu appears to have unique properties for example, the congener Ag shows no catalytic activity. Thus, the investigation of the differences between Cu and Ag on Si surfaces can help in understanding the catalytic process. Furthermore, the bonding of noble metal atoms to Si surfaces is of great importance in the physics and chemistry of electronic devices. 

Fig.6 Binding energies of Cu (full lines) and Ag (broken lines) on a Si(lll) surface. The perpendicular distance between the adsorbate atoms and the plane of the surface silicon atoms is denoted by h. Hollow, top, and bridge positions of the adsorbate atoms are indicated by the labels A, B, etc. as shown in the insert, u corresponds to an unrelaxed and r to a relaxed geometry of the neighboring surface Si atoms (after Ref.47)...

Allongue P, VUleneuve De CH, Moiin S, Boukherroub R, Wayner DDM (2000) The preparation of flat H-Si(lll) surfaces in 40% NH4F revisited. Electrochim Acta 45 4591-4598... 

Takahashi M, Todorobaru M, Wakita K, Uosaki K (2002) Heteroepitaxial growth of CdTe on a p-Si(lll) substrate by pulsed-light-assisted electrodeposition. Appl Phys Lett 80 2117-2119... 

This technique also appears as a very promising one, since there is no restriction concerning the nature of the adsorbate and the substrate. In fact, Co has been deposited successfully on a Au(lll) surface by this technique. This is not possible by means the TILMD technique described above, since due to the fact that the cohesive energy of Co is larger than that of An (4.39 vs 3.93 eV), the interaction of a Co-loaded tip with a An surface would lead to a hole on the substrate. Si(lll)... 

SECM has also been used to deposit a gold microstructure on n-Si(lll) and indinm oxide. In these experiments, Au is dissolved anodically from the ultramicro electrode under constant potential according to the reaction... 

Smith and co-workers (194) have used this chemistry to prepare carboxyl-modified Si(lll) surfaces at which polylysine-tethered DNA is electrostatically adsorbed (Fig. 60). An alternative approach involved covalent attachment of a pre-synthesized oligonucleotide bearing a terminal carboxyl group to an amine-modified Si(001) surface (195). 

Fiq. 60. Schematic illustrating electrostatic immobilization of DNA to a carboxyl-modified Si(lll) surface. Reproduced with permission from Ref. (194). Copyright 2000, American Chemical Society. 

---