Luminescent iron disilicide film growth by metal-organic chemical vapor deposition

Semiconducting iron disilicide (beta-FeSi2) films were epitaxially grown on the Ag-layer pre-coated Si(111) substrates with an initial beta-FeSi2 layer by the metal-organic chemical vapor deposition method. These beta-FeSi2 films had (101)-preferred orientations, and their crystal quality was improved as the growth temperature increased from 893 to 1093 K. The photoluminescence (PL) intensity of the (101)-oriented beta-FeSi2 films grown at 973 K was larger than those of beta-FeSi2 films at the other deposition temperatures, which indicates the decrease of the density of nonradiative recombination centers in beta-FeSi2. A clear A-band emission originated from beta-FeSi2 was observed for these films up to 285 K. This pronounced PL intensity enhancement from beta-FeSi2 is attributed not only to the crystallinity evaluated by XRD measurement but also to the decrease in density of thermal equilibrium Si vacancy in beta-FeSi2.