Correlation between surface charge accumulation and excitation intensity dependent red-shifted micro-photoluminescence of Si-implanted quartz with embedded Si nanocrystals

Abstract

The excitation intensity dependency of nanocrystallite Si (nc-Si) related micro-photoluminescence (mu-PL) from the multi-recipe Si-implanted quartz is characterized. The mu-PL at 724 nm contributed by nc-Si with 3-4 nm diameter is maximized after annealing at 1100degreesC for 3 hours. By increasing the excitation intensity from 10 kW/cm(2) to 300 kW/cm(2), the mu-PLs of 1-hr and 3-hr annealed quartz significantly red-shift from 723 nm to 725 nm and from 724 nm to 735 nm, respectively. This can be explained by the anomalous quantum stark effect due to a surface electric field oriented from photo-ionized nc-Si dots to quartz surface. After 1-hr illumination at power of 300 kW/cm(2), the mu-PL peak wavelength of 3-hr annealed sample is further red-shifted by 2.5 nm. By measuring the accumulated surface charges built up during optical excitation process, the correlation between excitation -intensity dependent PL wavelength red-shift and the photo-ionized nc-Si surface electric-field related quantum stark effect is primarily elucidated.