Hydrogen passivation was applied to the initial epitaxial growth of n-type β-FeSi 2 thin films on p-type Si(111) substrates by facing-targets direct-current sputtering (FTDCS) in order to reduced the formation of interface states and terminate dangling bonds in the β-FeSi 2 films, and the passivation effects were studied on basis of the electrical evaluation results of the formed n-type β-FeSi 2/p-type Si heterojunction photodiodes. The initial growth was made at different gas in-flow H 2/Ar ratios ranging from 0 to 0.2. The photodetection performance of the photodiode fabricated at the ratio of 0.2 was markedly improved as compared to those of the other samples. The quantum efficiency and detectivity were 2.08 % and 1.75 × 10 10 cm√Hz/W, respectively. The sample exhibited the minimum junction capacitance density of 9.2 nF/cm 2. The enhanced photo-detective performance should be mainly because dangling bonds that act as trap centers for photocarriers are effectively inactivated by the passivation.