Enhanced ultraviolet–visible cathodoluminescence from Ar+ beam-induced nano-patterned silicon

Cathodoluminescence (CL) of 60 keV Ar ion beam-induced ripple patterned Si in a high resolution scanning electron microscope (HRSEM) shows strong room temperature (RT) luminescence bands compared to a nonpatterned or patterned recrystallized Si. Site-specific CL spectroscopy and imaging data indicate while the top and front surface of ripples contribute predominantly to the red and near infra-red (IR) emission at image and 750 nm respectively, the back surface contributes mostly to ultraviolet (UV) emission at image. When the patterned sample is recrystallized after high temperature annealing, one observes a blue shift of the red peak to a yellow peak at image. Nanostructured Si of varying sizes (image) located around amorphous/crystalline (a/c)-interface and beyond it appears to be probable origin of luminescence observed in the present study.