Optical absorption and photoluminescence studies of beta-FeSi2 prepared by heavy implantation of Fe(+) ions into Si

Single-phase polycrystalline beta-FeSi2 formation up to the surface was attained by heavy implantation of Fe+ ions into Si and subsequent two-step annealing. Its optical absorption and photoluminescence characteristics were systematically examined as a function of second-step annealing temperature and its duration time. Findings indicated that the implanted layer is composed of polycrystalline precipitates of beta-FeSi2 with a small amount of Si. The type of the optical transition and the inverse logarithmic slope of the Urbach tail were studied.