Quantum confinement effect in electroluminescent porous silicon

Abstract

The voltage-tuned electroluminescence (EL) of n-type porous silicon (PS) in a persulphate solution under cathodic polarization was studied. A blue shift with the increase of cathodic polarization and a time-dependent red shift at constant potential of EL spectra have been observed. To investigate the voltage tuning mechanism and luminescence quenching mechanism for the electroluminescence of PS, FT-IR, AFM and electrochemical methods were used. The results show that the voltage-tuned electroluminescence can be attributed to the selective excitation of different sizes of PS crystallites, which agrees with the “quantum confinement model” in PS luminescence.