Backscattering of low-energy (0–8 eV) electrons by a silicon surface

An experimental apparatus and method for investigating elastic and inelastic backscattering (180°) of low-energy (0–8 eV) monoenergetic electrons by a solid surface are described and the first results are presented for the reflection of electrons by samples of pure single-crystalline silicon with a polished surface (Si), doped p-type single-crystalline silicon with a porous surface (Si-p) as well as H2O and H2O2 passivated porous samples, Si-p + H2O and Si-p + H2O2. A structure due to the excitation of surface plasmons has been observed for the first time in the loss spectra. Features corresponding to a resonance excited state of molecular nitrogen adsorbed on the surface of porous silicon have been observed in the constant residual energy spectra.