Keywords: electron field emission, porous silicon, resonance tunnelling, photoluminescence, diamond-like carbon film, current stability, nanocrystals, energy band diagram, work function, field enhancement coefficient, nanotechnology, low anodisation
Electron field emission from porous silicon prepared at low anodisation currents
The dependence of electron field emission (FE) characteristics of porous silicon (por-Si) prepared by anodisation at low current density without external bias is investigated. Effective electron FE from por-Si on p-Si flat surface was revealed. With growth of anodisation current (from 1 mA/cm² to 5 mA/cm²) the electron FE efficiency was decreased. Resonance tunnelling at electron field emission from por-Si was observed. The por-Si coating with thin diamond-like carbon film allowed the increase of the efficiency and stability of electron emission current significantly. The obtained experimental results on electron FE from por-Si on flat p-Si silicon surface were explained on the basis of electrical field enhancement coefficient growth, existence of dipole Si-H layer, lowering of por-Si electron affinity and growth of native SiO2 oxide on silicon surface. The model for explanation of resonance tunnelling from por-Si was proposed.