Electroluminescence properties of porous silicon nanostructures with optimum current density of photo-electrochemical anodisation

P-type silicon wafer (<;100>; orientation; boron doping; 0.75 ~ 10 Ωcm^-1) was used to prepare samples of porous silicon nanostructures (PSiNs). All samples have been prepared by using photo-electrochemical anodization. A fixed etching time of 30 minutes and volume ratio of electrolyte, hydrofluoric acid 48% (HF48%) and absolute ethanol (C₂H₅OH), 1:1 were used for various current densities, J. There were sample A (J=10 mA/cm²), sample B (J=20 mA/cm²), sample C (J=30 mA/cm²), sample D (J=40 mA/cm²) and sample E (J=50 mA/cm²). Photoluminescence (PL) and EL spectra were investigated. Maximum peak position of PL spectrum at about ~675 nm, while the maximum EL spectrum at about ~650 nm (which is similar to the PL spectrum).