Low-power wavelength modulation in size-controlled Si nanocrystals using quantum confined Stark effect

Abstract

We report on the quantum confined Stark effect coupled with a permanent built-in electric dipole moment in size-controlled Si nanocrystals (SiNCs) investigated under steady state conditions by photoluminescence spectroscopy. The study was conducted on samples with SiNC layer thicknesses between 2 nm and 5 nm. The emission spectra of the samples subjected to electric field magnitudes of up to 5 × 108 V/m were analyzed in terms of the dependency of the spectral shift on field magnitude and SiNC size. A clear trend of red shift along with increasing dipole separation was observed with increasing SiNC size. Experimental results show a high degree of accuracy to the model based on the time independent perturbation theory approximation for a biased quantum well. We propose a potential application for size-controlled SiNCs in photon detection in the near infrared band based on the studied phenomena as well as the use of SiNCs as a model platform for further study of the Stark effect in quantum confined structures as a whole.