Silicon oxide

About: Silicon oxide is a research topic. Over the lifetime, 22220 publications have been published within this topic receiving 260986 citations.

Effects of Water on Tribochemical Wear of Silicon Oxide Interface: Molecular Dynamics (MD) Study with Reactive Force Field (ReaxFF).

Abstract: Molecular dynamics (MD) simulations with the ReaxFF reactive force field were carried out to find the atomistic mechanisms for tribochemical reactions occurring at the sliding interface of fully hydroxylated amorphous silica and oxidized silicon as a function of interfacial water amount. The ReaxFF-MD simulations showed a significant amount of atom transfers across the interface occurs during the sliding. In the absence of water molecules, the interfacial mixing is initiated by dehydroxylation followed by the Si-O-Si bond formation bridging two solid surfaces. In the presence of submonolayer thick water, the dissociation of water molecules can provide additions reaction pathways to form the Si-O-Si bridge bonds and atom transfers across the interface. However, when the amount of interfacial water molecules is large enough to form a full monolayer, the degree of atom transfer is substantially reduced since the silicon atoms at the sliding interface are terminated with hydroxyl groups rather than forming interfacial Si-O-Si bridge bonds. The ReaxFF-MD simulations clearly showed the role of water molecules in atomic scale mechanochemical processes during the sliding and provided physical insights into tribochemical wear processes of silicon oxide surfaces observed experimentally.

Intense blue-white luminescence from carbon-doped silicon-rich silicon oxide

Abstract: The effect of carbon doping on the enhancement of visible luminescence from silicon-rich silicon oxide (SRSO), which consists of Si nanoclusters embedded inside a SiO2 matrix, is investigated. C-doped SRSO films were fabricated by electron cyclotron resonance-plasma enhanced chemical vapor deposition method using SiH4, O2, and CH4 source gases followed by a high-temperature anneal. Intense blue-white visible luminescence, visible to the naked eye under daylight conditions, was observed from the film with a nearly equal amount of C and excess Si (∼16 at. %) after an anneal at 950 °C. Furthermore luminescence could be tuned from 1.8 to 2.5 eV by controlling the C to excess Si ratio, the C content, and the anneal temperature. Taken together with the infrared absorption spectra, these results indicate that the luminescence is attributed to exciton recombination in C-incorporated Si nanoclusters.

Effect of nitride passivation on the visible photoluminescence from Si-nanocrystals

Abstract: The effect of nitride passivation on the visible photoluminescence from nanocrystal Si (nc-Si) is investigated. Silicon-rich silicon nitride (SRSN) and silicon-rich silicon oxide (SRSO), which consist of nc-Si embedded in silicon nitride and silicon oxide, respectively, were prepared by reactive ultrahigh vacuum ion beam sputter deposition followed by a high temperature anneal. Both SRSN and SRSO display photoluminescence peaks after high temperature annealing, coincident with the formation of Si nanocrystals, and similar changes in the peak luminescence position with the excess Si content. However, the luminescence peak positions from SRSN are blueshifted by about 0.6 eV over that of comparable SRSO such that its luminescence peaks in the visible range. The results demonstrate that control of the surface passivation is critical in controlling the nc-Si luminescence, and indicate the possibility of using nitride-passivated nc-Si for visible luminescence applications including white luminescence.

Guided self-assembly of metallic nanowires and channels

Abstract: A method is presented to form metallic nanowires and nanochannels by guided self-assembly. The method relies on an initial plasma-enhanced chemical vapor deposition of a silicon oxide film with altered chemistry on a silicon wafer, and the cracking of the film due to tensile stresses upon annealing. The fabricated stress concentration features on the Si substrate control the number of cracks and their orientation. These cracks are then filled with electroless nickel, and the subsequent removal of SiO2 produces a controlled network of nanowires of about 100 nm in dimension. In addition to nanowires, nanobridges, and nanocantilevers have also been fabricated by releasing the wires, confirming that the resulting structures are rather robust.

Embedded catalyst for atomic layer deposition of silicon oxide

Abstract: Catalyzed atomic layer deposition from a reduced number of precursors is described. A deposition precursor contains silicon, oxygen and a catalytic ligand. A hydroxyl-terminated substrate is exposed to the deposition precursor to form a silicon bridge bond between two surface-bound oxygens. The surface-bound oxygens were part of two surface-bound hydroxyl groups and the adsorption of the deposition precursor liberates the hydrogens. The silicon atom is also chemically-bound to one or two additional oxygen atoms which were already chemically-bound to the silicon within a same deposition precursor molecule. At least one of the additional oxygen atoms is further chemically-bound to the catalytic ligand either directly or by way of a hydrocarbon chain. Further exposure of the substrate to moisture (H2O) results in displacement of the additional oxygen which are replaced by hydroxyl groups from the moisture. The surface is again hydroxyl-terminated and the process may be repeated. The catalytic nature of the reaction enables the deposition to occur at low substrate temperatures. The chemically-embedded nature of the catalyst increases the deposition per cycle thereby reducing the number of precursor exposures to grow a film of the same thickness.