P H bonds in the surface unit cell of P rich ordered InP 001 grown by metalorganic chemical vapor deposition

The Fourier transform infrared spectrum of the MOCVD grown smetalorganic chemical vapor depositiond P rich ordered InP 001 surface was measured in ultrahigh vacuum applying attenuated total reflection. The surface was measured without carrying out any post transfer surface preparation. The low energy electron defraction pattern showed the well known 2x1 structure with streaks in the [ 110] direction. After exposure to activated deuterium, the different infrared spectrum revealed a pronounced peak at 2308 cm 1, which was ascribed to P H bonds. Polarization dependent spectra showed the dipole moments of the P H bonds oriented only in f001g and [ 110] directions. A weak 0.8 cm 1 splitting was measured between the symmetric and antisymmetric modes of two neighboring P H bonds. These observations provide direct proof for two oriented P H bonds as in the surface unit cell proposed by Hahn and Schmidt [Surf. Rev. Lett. 10, 163 2003 ]. Additional much smaller peaks with different polarization behavior varied greatly for different samples and were ascribed to defects or impurities