A combined RHEED and photoemission comparison of the GaP and InP(0 0 1) (2×4) surface reconstructions

In this work, we compare the (2×4) reconstructions of GaP and InP(0 0 1) surfaces. Two different (2×4) reconstructions are detected by reflection high energy electron diffraction for both materials. Photoemission experiments reveal that the high temperature one is cation-rich whereas the low temperature one is anion-rich. High resolution spectra on the high temperature (2×4) reconstructions exhibit surface components which are in agreement with what is expected from the mixed-dimer model in both cases. As regards the low temperature (2×4) GaP, a second surface component on the P 2p core level line reveals that two different atomic sites exist for the P-atoms at the surface which is different from the β2 (2×4) geometry. The low temperature (2×4) InP is more phosphorus-rich and turns to be a mixture between the (2×1) and the high temperature (2×4) reconstructions.