Surface/interface-related optical properties in Si nanodisks fabricated by neutral-beam etching using bio-templates

Abstract The authors study surface/interface-related optical properties in Si nanodisks (NDs) fabricated by neutral-beam etching using bio-templates. Photoluminescence (PL) spectra and the transient properties are compared between different barrier materials of SiO 2 and SiC. The PL spectral shape depends on the barrier material, indicating effects of oxide formation and/or oxygen atoms on the surface of the Si ND. The transient PL shows nanosecond-scale transition of carriers in surface-related quantum states in the ND. Temperature dependences of the PL intensity show that the activation energy responsible for the electron escape from the Si-ND at near room temperature in the case of SiC barrier agrees well with the conduction band offset, whereas that in the case of SiO 2 barrier is significantly lower than the expected offset. The latter discrepancy suggests that the electronic band structure at the interface of Si-ND/SiO 2 can be largely affected by dielectric screening due to oxygen atoms in the SiO 2 .