Raman scattering at the (111) and (1¯1¯1¯) surfaces ofn- andp−InAs

Resonance-enhanced Raman scattering by LO phonons has been used to obtain information on the nature of the $A\left(111\right)\mathrm{}$ and $B\left(\overline{1}\overline{1}\overline{1}\right)$ surfaces of $n$- and $p-\mathrm{InAs}$ in air. The marked differences in the behavior of the forbidden LO-phonon scattering at the (111) and ($\overline{1}\overline{1}\overline{1}$) surfaces of $n$- and $p-\mathrm{InAs}$ reflect the differences in location of the Fermi level at the two surfaces. Both (111) and ($\overline{1}\overline{1}\overline{1}$) surfaces of $n-\mathrm{InAs}$ are depleted of free carriers in contrast to (100) surfaces which are accumulated.