Silicon nanocone arrays with metal silicide （Fe and Cr）-enriched apexes are fabricated on Si （100） substrate by the Ar＋ ion bombardment method. The nanocone arrays show excellent field emission properties. A high current density （J） of -0.03 mA/cm^2 under a field of -3 V/μm, a very low turn-on field of -1.4 V/μm, and a very large enhancement factor of -9466 are also obtained. The emission J of Si nanocone arrays remains extremely stable for long periods of time （24 h）.
Photoluminescence （PL） conversion of Si nanoparticles by absorbing ultraviolet （UV） lights and emitting visible ones has been used to improve the efficiency of crystalline Si solar cells. Si nanoparticle thin films are prepared by pulverizing porous Si in ethanol and then mixing the suspension with a SiO2 sol-gel （SOG）. This SOG is spin-deposited onto the surface of the Si solar cells and dries in air. The short-circuit current as a function of Si nanoparticle concentration is investigated under UV illumination. The maximal increase is found at a Si concentration of 0.1 mg/mL. At such concentration and under the irradiation of an AM0 solar simulator, the photoelectric conversion efficiency of the crystalline Si solar cell is relatively increased by 2.16% because of the PL conversion.
