In order to improve the photoluminescence (PL) of semiconducting beta-FeSi2 films, as-grown films were thermally annealed under various conditions. The films were fabricated either by an ion beam sputter deposition (IBSD) or a molecular beam epitaxy (MBE) method. For both IBSD-grown and MBE-grown films, high temperature annealing in a flow of Ar gas or air led to drastic enhancement of PL intensity. Furthermore, PL characteristics were found to depend on the annealing atmosphere, where it was shown that air was more effective than Ar gas. (c) 2005 Elsevier B.V. All rights reserved.