Preparation and Characterization of Crystalline Silicon by Electrochemical Liquid-Liquid-Solid Crystal Growth in Ionic Liquid.

The electrodeposition at low temperature for the direct growth of crystalline thin films without any templating agent in ionic liquid (IL) is a relatively new electrochemical synthetic strategy. This work studied the role of the deposition temperature, deposition time, and different working electrodes in the electrodeposition of crystalline Si thin films from the byproduct silicon tetrachloride in IL at low temperature. X-ray diffraction (XRD) revealed that the as-deposited Si films were crystalline at the temperature of 80 °C. Scanning electron microscopy (SEM) and Raman spectroscopy further indicated that the crystalline quality of the as-deposited silicon film was relatively the best when the electrodeposition time reached 1 h at the temperature of 100 °C; excessive electrodeposition would yield amorphous silicon on the surface of the as-deposit crystalline Si, which decreased the crystal quality of the Si film. The SEM and XRD, respectively, revealed that the crystal structure of Si yielded on e-InGa was significantly different from that produced on Ga and more impurities existed in the film. Research on the influence of these parameters on crystallinity and morphological characteristics of Si gives better control over the growth of crystalline Si thin films for specific applications.