Dynamics of electron scattering between bulk states and the C 1 surface state of InP(100)

Abstract

Hot electron dynamics was investigated, with a focus on scattering between bulk states and the C1 surface state that is formed on the (2×4)-reconstructed In-rich surface of InP(100). The latter surface was prepared via metal organic chemical vapor deposition (MOCVD) and monitored by reflectance anisotropy spectroscopy (RAS/RDS). Two-color twophoton photoemission (2PPE) was employed with laser pulses of about 50 fs duration. Hot electrons were generated in bulk states about 0.5 eV above the C1 surface state, thereby avoiding any significant direct optical population of the surface state. A time constant of 35 fs was determined from the experimental data for electron scattering from isoenergetic bulk states to the C1 surface state by analyzing the rise of a C1-specific peak in the 2PPE spectrum. The decay of this C1 peak was ascribed to energy relaxation of the photo-generated electrons to bulk states below the surface state. Analogous measurements were carried out with a (2×1/2×2)-reconstructed P-rich surface of InP(100) that was also grown via MOCVD. No sign of a surface statewas detected in the 2PPE spectra for the latter surface in the corresponding energy range of the conduction band.