Iron disilicide photochemical diode with Au-promoter

半导体二硅化铁(β-FeSi2)作为一种适用于光纤通信波长的光电探测器和硅基发光体，引起了人们极大的关注。这是因为β-FeSi2的禁带宽度小于0.80 eV，在1 eV处有很大的光吸收系数，大于1e5/cm。此外，这种半导体材料含有比传统化合物半导体中使用的元素更丰富、毒性更低的元素。在本报告中，我们报道了利用半导体工艺中常用的金属-有机化学气相沉积(MOCVD)方法在硅粉表面制备Au电极的β-FeSi2光化学二极管的新方法。此外，我们还研究了这种光化学二极管在紫外光和甲醛水溶液中的可见光照射下的析氢情况。

Semiconducting iron disilicide (beta-FeSi2) has been attracting a great deal of attention as a photo-detector and Si-based light emitter operating at wavelengths suitable for optical fiber communications. This is because beta-FeSi2 has a band gap less than 0.80 eV and a very large optical absorption coefficient over 1E+5 /cm at 1 eV. Moreover, this semiconducting material is composed of the elements that are naturally abundant and less toxic than the elements used in conventional compound semiconductors.In this report, we report on the novel fabrication method of beta-FeSi2 photochemical diode with Au electrode on the surface of Si powder by using metal-organic chemical vapor deposition (MOCVD) method which is general in semiconductor process technology. Moreover, we repot on the hydrogen evolution over this photochemical diode under irradiation of not only UV but also visible light from formaldehyde aqueous solution.