Resonant Raman scattering in InP

Electron-Phonon Coupling at InP(110) SurfacesInvestigated by Resonant Raman Spectroscopy

“…Obviously scattering intensities of surface phonons are strongly dependent on laser photon energies. Apart from changes in scattering intensities, the eigenfrequencies of the surface and bulk phonon modes increase by about 3-4 cm À1 upon cooling to 50 K. The intensity scales of the spectra have been corrected for the penetration depth of the light [30] and the known resonance behaviour of the bulk TO phonon [8] in order to take into account the apparative response. Since this correction is different for each laser photon energy, the intensities of bulk phonons cannot be compared on an absolute intensity scale before an inverse correction for the penetration depth of light has been done.…”

“…This result may indicate a vanishing deformation potential D j for the high frequency mode at the surface band gap at 2.80 eV or an anti-resonance due to destructive interference of different scattering contributions. [30] and the known resonance behaviour of the bulk TO phonon [8], in order to take into account the apparative response Both gap modes are going into a strong resonance for photon energies at 3.00 and 3.05 eV. In this spectral range, the RA spectra reveal a surface transition at 2.97 eV.…”

“…4. Raman resonance profiles of the a) lower and b) higher frequency gap modes in comparison with the TO resonance [8]. Previous Raman data at RT (black squares [12,13]) and new data at RT (open squares) and at 50 K (open circles).…”

Raman Scattering from Surface Phonons

“…A different resonance behaviour for the two gap modes is found, a maximum at 2.81 eV for the lower frequency gap mode and a maximum at 3.00 eV for the higher frequency gap mode. For further analysis the normalized intensities (I s aI TO ) were corrected well for the penetration depth of the light [34] and the known resonance behaviour of the bulk TO phonon [20] in order to take into account the apparative response. In Fig.…”

“…RRS can be regarded as a form of modulation spectroscopy where the microscopic vibration modulates the electric susceptibility c. For photon energies in the visible range Raman scattering in semiconductors is mediated through electronic interband transitions, thus the Raman tensor elements depend on (dcadw). The scattered intensity can then often (for example for the TO-InP bulk phonon [20]) be written as…”