Induced quantum-Fano effect by Raman scattering and its correlation with field emission properties of silicon nanowires

Here, we report the effect of crystal size and aspect ratio on field emission (FE) properties of silicon nanowire (Si-NWs) fabricated onto n-type Si (100) using metal-induced chemical etching (MIE) technique. The optical band gap calculation from the diffuse reflection spectra reveals the decrement in the band gap of Si-NWs from 1.98 to 1.69 eV. Here, band gap-dependent hyperbolic band model has been used to estimate the crystal size present in Si-NWs, which shows the quantum confinement (QC) effect. XPS studies indicate that the samples clearly exhibit the presence of oxidation state of Si (0) in Si-NWs. Long-range order Raman scattering has been analyzed for confirmation of quantum-Fano effect presence in Si-NWs due to red shift and asymmetry behavior of Raman band, which has been observed from Si-NWs as compared to its bulk counterpart. Moreover, a theoretical Raman line fitting model has been used to estimate the crystal size present in Si-NWs. The electron field emission properties of Si-NWs have been studied using current-voltage (I-V) measurements followed by a theoretical analysis through the Fowler-Nordheim (F-N) equation as a function of the crystal size. The electron field emission studies show the smaller crystal size has a lower turn-on voltage. Moreover, it has been found that the aspect ratio of Si-NWs linearly varies with the field enhancement factor.