The characteristic carrier–Er interaction distance in Er-doped a-Si/SiO2 superlattices formed by ion sputtering

The characteristic interaction distance between Er3+ ions and carriers that excite them in Er-doped a-Si/SiO2 superlattices is investigated. Superlattice thin films consisting of 12 periods of a-Si/SiO2:Er/SiO2/SiO2:Er layers were deposited by ion sputtering and subsequent annealing at 950 °C. The dependence of the Er3+ photoluminescence intensity on the thickness of the Er-doped SiO2 layers is well-described by an exponentially decreasing Er-carrier interaction with a characteristic interaction distance of 0.5±0.1 nm.