Iron disilicide photochemical diode with Au-promoter

半导体二硅化铁（β - fesi2）作为一种适合于光纤通信波长的光探测器和硅基光发射器，已经引起了人们的广泛关注。这是因为β - fesi2具有小于0.80 eV的带隙和非常大的光学吸收系数，在1ev下超过1E+5 /cm。此外，这种半导体材料是由天然丰富的元素组成的，比传统化合物半导体中使用的元素毒性小。本文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，我们还报道了该光化学二极管在甲醛水溶液紫外线和可见光照射下的析氢过程。

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.