Er 3+ photoluminescence properties of erbium-doped Si/SiO2 superlattices with subnanometer thin Si layers

The effect of the Si layer thickness on the Er3+ photoluminescence properties of the Er-doped Si/SiO2 superlattice is investigated. We find that the Er3+ luminescence intensity increases by over an order of magnitude as the Si layer thickness is reduced from 3.6 nm down to a monolayer of Si. Temperature dependence of the Er3+ luminescence intensity and time-resolved measurement of Er3+ luminescence intensity identify the increase in the excitation rate as the likely cause for such an increase, and underscore the importance of the Si/SiO2 interface in determining the Er3+ luminescence properties.