NEUTRALIZATION OF H− NEAR Si(100) SURFACES

We calculated the electronic structure of the unreconstructed Si(100) surface within an extended screened Thomas-Fermi pseudopotential method [1]. We derive an effective electronic potential (Fig. 1) from which we obtain singleparticle Kohn-Sham orbitals and their energies. Our calculated density of states (DOS) is in good agreement with the observed DOS from photoemission measurements on Si surfaces [2]. We study the charge transfer dynamics between H− ions with kinetic energies between 50 and 150 eV within the Newns-Anderson model. We calculate the negative ion survival probability P (H−) = |Saa| 2 + ∑ k<kF |Sak| 2 in terms of the survival amplitude Saa of the initial charge state of the ion and amplitudes Sak for capture from the initially occupied Fermi sea of the surface (Fig. 2)