Dominant growth of higher manganese silicide film on Si substrate by introducing a Si oxide capping layer

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. •The multi-phase formation will be hindered by a SiOx capping layer on Si.•The single phase MnSi1.7 can grow into micron scale without phase separation.•The band gap energy of the MnSi1.7 film agrees well with the calculated one.