STRUCTURAL AND ELECTRICAL CHARACTERIZATION OF SILICON NANOPARTICLES PRODUCED USING A LOCALLY FABRICATED MILLING MACHINE

Abstract

Fundamental understanding and relationship between properties of materials and materials dimension particularly in the nanometre range have sparked much interest in material research at nanometre level. In this research work, two types of silicon wafers, a P-type and N-type with <100> orientation, were milled separately to obtain silicon nanoparticles using locally fabricated milling machine. The structure of the milled silicon nanoparticles after 25 hours of milling was investigated using X-ray diffraction to obtain the average particle size or crystallite size. The result shows a structural transformation of the starting single crystalline wafer to a polycrystalline phase nanoparticles. There is no noticeable broad hump which is an indication of an amorphous phase. The average crystallite size obtained using the Scherer’s equation was 81nm which is an indication of grains in the nanometre range. The silicon powders produced were then dispersed separately in styrene acrylic binder to form a P-typed and N-typed nanocomposite inks with different ratio of the powder dispersed in the binder. Using the screen printing method, a typical PN layer of the inks was printed on a ceramic substrate to demonstrate a printable solar cell structure. The fabricated solar cells were then characterized using a homemade solar simulator to obtain meaningful transport properties and the effect of light on the extracted parameters.