The microstructures of the as-sputtered amorphous silicon-rich oxide (SiO x ) films were investigated by using a combination of X-ray photoelectron spectroscopy (XPS) and Raman microscopy. XPS analysis reveals that the as-sputtered amorphous SiO x films are chemically inhomogeneous. Raman spectra and valence band XPS spectra suggest the formation of amorphous Si nanoclusters in the as-sputtered amorphous SiO x films. The size of these nanoclusters depends on the Si concentration in the films. The formation of amorphous Si nanoclusters was attributed to the high kinetic energy and surface migration of the sputtered Si atoms. It is found that the as-sputtered amorphous SiO x films have a complex structure consisting nanoscale cluster of amorphous Si core with suboxides shell embedded in the amorphous SiO2 matrix.

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Silica nanowires are usually synthesized by means of vapor liquid solid method with metal catalyst introduced at the top which will unambiguously affect the excellent light emission properties of silica nanowires in optoelectronic devices and optical signal sensors. In this study, silicon dioxide nanowires without traces of catalyst are grown via rapid thermal annealing of magnetron sputtered amorphous carbon film doped with silicon. These high density silicon dioxide nanowires were amorphous with a length longer than 20 m and a diameter of 30-140 nm. Detailed morphology and microstructure analysis are conducted with field emission scanning electron microscopy and high resolution transmission electron microscopy. Graphitization of carbon and oxidation of silicon during rapid thermal annealing were revealed by Raman and X-ray photoelectron spectroscopy. This study indicates that high growth rate of >6 m/min of high purity silicon dioxide nanowire is possible simply by sputtering followed by rapid thermal annealing and an additional heating treatment.

Magnetron sputtering has been used to deposit Ni-rich nickel oxide thin films. Based on the switching of lateral current conduction in the nickel oxide thin film between two in-plane electrodes, a planar write-once-read-many-times memory device has been demonstrated. The switching from a low-conductance state (i.e., the OFF state) to a high-conductance state (i.e., the ON state) is induced by a writing voltage, and it is irreversible due to the formation of tilted conductive filaments that are hard to be dissolved by the Joule heating effect. For 80 devices under test, the writing voltage is in a narrow range of 2.0À3.5 V and the ON/OFF resistance ratio is larger than 10 5 at the reading voltage of 0.3 V. An excellent reading endurance (10 6 readings) for both ON and OFF states is demonstrated. The device is promising in low-power applications as it can operate at ultra-low voltages (e.g., the reading voltage can be below 100 mV).

Silicon nanocrystals are synthesized by reactive magnetron sputtering to distribute throughout the gate oxide layer. Electroluminescence (EL) from amorphous silicon dioxide (a-SiO2) film embedded with Si nanocrystals (nc-Si) has been studied under various gate voltages. Both the integrated EL intensity and the gate current first increase and then decrease with increasing gate voltage. The decrease in EL intensity is ascribed to the charging up of the nc-Si associated trapping centers. The EL intensity can be partially recovered by application of positive electric stress to release part of the trapped charges.