Abstract
A surfactant free growth method was proposed to get thick MnSi∼1.7 film by exposure of Si(111) substrates to MnCl2 vapor in quartz ampoules. Prior to the growth of silicide film, an amorphous nano SiOx capping layer was introduced on the Si substrate. The capping layer changes the elemental diffusion flux to the reaction interface and facilitates the growth of single phase MnSi∼1.7 film. Optical absorption spectrum demonstrates the existence of a direct band gap∼ 0.78 eV, which agrees well with the theoretical one obtained by density functional theory modeling.