Evidence for an intrinsic reconstructed layer at the surface of InSb

Magneto-optical and Raman-scattering experiments at the $E_1$ edge of InSb are discussed. Included are details of observed Landau-level structure in this compound, as well as in the related semiconductors GaSb, Ge, and HgTe. Essential features of these experiments are interpreted using a model which assumes a thin reconstructed layer to occur on the InSb surface. The properties of this layer are found to be sensitive to various surface treatments including annealing and etching. Landau levels at the InSb $E_1$ edge have been examined as a function of bulk carrier concentration, and the attenuation of our spectra for both large $n$ (> ${10}^{17}$ ${\mathrm{cm}}^{-3\mathrm{}}$) and $p$ (> ${10}^{18}$ ${\mathrm{cm}}^{-3\mathrm{}}$) doping could arise from tunneling from the surface layer to the bulk and vice versa. A relation between this peculiarity in optical spectra and long-known infrared band shifts is suggested.