Papers by Keyword: SiO_x

Abstract: Electrochemical reactions occurring at a SiO_x electrode were investigated to gain insight about the effects of film-forming additives, such as vinylene carbonate (VC), ethylene sulfite (ES) and 1,3-propane sultone (PS), on the formation of a solid electrolyte interface (SEI) on the SiO_x electrode. The SEI formed in the presence of PS was found to have the smallest resistance, resulting in low irreversible capacity and good cycle performance.

Abstract: he negative differential capacity has been observed in case of MIS structures with SiO_x and Si_xO_yN_z films containing Si nanoclusters. It has been shown that existence of negative differential capacity depends on charge state of Si nanoclusters or electron traps　in the insulating matrix. In case of Si_xO_yN_z films the two peaks have been revealed in C-V characteristics connected with Si nanoclusters and electron traps. The low-temperature annealing of Si_xO_yN_z films in hydrogen passivates the electron traps caused by Si dangling bonds and as a result the peak in C-V characteristics connected with electron traps disappears. The following low-temperature annealing in vacuum caused the some effusion of hydrogen from the film and appearance of electron traps and connected with them capacity shoulder on C-V characteristics. It has been shown, that the frequency and temperature dependences of the negative differential capacitance in C-V curves can be successfully used for the determination of nanoclusters and traps parameters for the samples with the nanoclusters embedded in SiO₂ or Si_xO_yN_z films.

Abstract: The structural and optical properties of Si nanocrystal (Si-nc) embedded in a matrix of off-stoichiometric silicon oxide (SiO_x, x<2) films prepared by hot filament chemical vapor deposition technique were studied. The films emit a wide photoluminescent spectra and the maximum peak emission shows a blue-shift as the substrate temperature (Ts) decreases. Also, a wavelength-shift of the absorption edge in transmittance spectra is observed, indicating an increase in the energy band gap. The Si-nc’s size decreased from 6.5 to 2.5 nm as Ts was reduced from 1150 to 900 °C, as measured through High Resolution Transmission Electron Microscopy analysis. A combination of mechanisms is proposed to explain the photoluminescence in the SiO_x films, which involve SiO_x defects and quantum confinement effects.

Abstract: X-ray Diffraction and Reflectivity, Transmission Electron Microscopy and Atomic Force Microscopy were applied to study the effect of thermal annealing on the properties of thin SiOx films (~ 15 nm) prepared by thermal evaporation of SiO in vacuum. It has been shown that furnace annealing at 1000 oC causes phase separation and formation of uniformly distributed Si nanocrystals into a SiO2 matrix. Clockwise hysteresis has been observed in the C-V curves measured and explained by assuming charging and discharging of the NCs with carriers, which tunnel from the Si substrate.

Abstract: Si-rich SiO₂ (SRSO) films were prepared by RF magnetron sputter techniques, and the structural and optical features of nanocrystalline Si (nc-Si) embedded in the SiO₂matrix were investigated in terms of post-deposition heat-treatment conditions. The SRSO thin films exhibited PL phenomena in the wavelength range of (450 ~ 500 nm). Post-deposition heattreatment at relatively high temperature like 1000 ~ 1100 °C increased the crystallinity of the films as well as the volume of the Si nanocrystallites (and SiO₂), and as a result, PL intensity was enhanced in the visible light region. The nc-Si embedded in SiO₂matrix is a few nanometers in size. It is believed that the Si nanocrystallites in the post-deposition annealed films are isolated and well passivated by SiO₂.