Polyoxometalate-assisted formation of CoSe/MoSe2 heterostructures with enhanced oxygen evolution activity

The heterostructured CoSe/MoSe2 hybrids was fabricated by a non-metal induced growth method for efficient oxygen evolution reaction (OER).

Lower Temperature Si Thin Films by Metal Induced Growth for Lower Cost Solar Cells

Metal induced growth (MIG) was used to form epitaxial thin films of microcrystalline Si (μc-Si). By substituting Al as the catalyst metal in place of the usual Ni, x-ray diffraction (XRD) confirmed that μc-Si was successfully grown at temperatures between 350-525°C. At 525°C, a preferred orientation of (220) Si was observed with additional (111) and (311) Si orientations, while a temperature of 350°C resulted in a shift in preferred orientation to (111) Si. The lower limit for Al thickness was found to be between 10-20 nm with little crystallization and a smooth surface observed at 10 nm with XRD and SEM, respectively. Electrical measurements on Schottky diodes revealed space-charge limited conduction (SCLC) with an exponential distribution of trap levels due to diffusion of Al atoms into the Si, which was supported by analysis with energy dispersive x-ray spectroscopy (EDX) near the film surface. By depositing a thin layer of Co on top of Al prior to sputtering, the films exhibited increased crystallinity and a more uniform surface likely due to increased confinement of Al atoms. Electrical measurements demonstrated a shift from SCLC to thermionic emission in resulting Schottky diodes.

Effects of Deposition Parameters on the Structure and Photovoltaic Performance of Si Thin Films by Metal Induced Growth

A metal-induced growth (MIG) process was employed to deposit thin films of microcrystalline silicon (μc-Si) for solar cell applications. Due to different grain orientations of the crystals, the absorption coefficient of μc-Si is about 10 times higher than the absorption coefficient of single crystalline Si. The properties of the Si film were investigated resulting from variations in several parameters. A range of Ni and Co thicknesses were examined from 7.5 nm to 60 nm including combinations of the two, while the dc sputtering power was stepped up from 150 W to 225 W. The structure of the resulting film was studied using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and x-ray diffraction (XRD). SEM of the film revealed that 5 hr of Si deposition at 150 W yields a film thickness of 6.5 μm and a maximum grain size of about 0.6 μm. EDS data showed that at the middle of the Si film the atomic percentage of the Si was 99.17%. XRD data showed that the dominant crystal orientation is {220}. To characterize the photovoltaic properties of the μc-Si, Schottky photodiodes were fabricated. Ni alone as the seed layer resulted in ohmic behavior. With Co only, MIG formed a rectifying contact with open-circuit voltage (V∝). The combination of Co layered over Ni formed better thin films and gave a Voc of 0.24 V and short-circuit current density (Jsc) of 5.0 mA/cm2 since the Co prevents Ni contamination of the top of the grown Si layer.

Solid-state growth of nickel silicide nanowire by the metal-induced growth method

Unique nanowire growth was accomplished at 575 °C by the metal-induced growth (MIG) method. This involved a spontaneous reaction between metal and Si. The deposited metal worked as a catalyst layer to grow nanowires in the solid state. Various metals (Ni, Co, and Pd) were used in MIG nanowire fabrication, and the Ni-induced case was successful in demonstrating that metal species should be the dominant factor for growing nanowires. The Ni to Si composition was studied by energy dispersive spectroscopy showing the Ni diffusion inside the nanowire as well as the Ni silicide layer. The practical application of the MIG nanowire was proved by fabricating nanoscale contacts.

Silicide Mediated Grown Silicon Thin Films for Photodiodes

ABSTRACTQuality Si thin films were grown by the metal-induced growth (MIG) method. Metal (Co, Ni, or mixing of Co and Ni) was thermally evaporated on a 200 nm-SiO2 coated Si wafer. Si sputtering was performed at 600 – 620 °C in a dc magnetron system. The reaction of Si and metal first formed a silicide (CoSi2 or NiSi2) layer and further Si sputtering grew a Si film above it. The grown Si films were practically fabricated for Schottky photodiodes and electrically measured under one sun scan illumination (100 mW/cm2).