Modifications of space charge layer on InP(110) surface induced by atomic hydrogen at very low exposures

The HREEL spectrum of InP(110) in the quasi-elastic peak region is strongly modified by the exposure to atomic hydrogen. From a detailed analysis of these modifications we have shown that (i) cleavage induced states in InP can have acceptor-like nature, as an “unavoidable” small upwards band bending was always present even on mirror-like cleaved surfaces; (ii) atomic hydrogen at very low exposures can neutralize these acceptor states, reducing to almost zero the pre-existing band bending; (iii) at high exposures, H induces new acceptor states inside the gap and, consequently, a new and larger band bending occurs at the surface, which reaches about 0.6 eV above 1000 L.