Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)
O 35.47: Poster
Tuesday, March 12, 2013, 18:15–21:45, Poster B1
Preparation of GaP/Si(111) quasi-substrates for III-V nanowire solar cells — •Weihong Zhao1,2, Agnieszka Paszuk1,2, Matthias Steidl1,2, Sebastian Brückner1,2, Anja Dobrich2, Johannes Luczak2, Peter Kleinschmidt1,3, Henning Döscher1,2, and Thomas Hannappel1,2,3 — 1Technische Universität Ilmenau, Institut für Physik, Fachgebiet Photovoltaik, D-98684 Ilmenau — 2Helmholtz-Zentrum Berlin, Institut für Solare Brennstoffe und Energiespeichermaterialien, D14109 Berlin — 3CiS Forschungsinstitut für Mikrosensorik und Photovoltaik, D99099 Erfurt
Meeting the demands of high-quality-low-cost photovoltaics, III-V nanowires grown on Si(111) substrates present a promising new solar cell concept. GaP buffer layer can be grown almost lattice matched on Si(111) substrates. Succesful nanowire growth requires atomically smooth/flat GaP(111)B surfaces. Therefore a suitable Si(111) surface preparation is crucial.We used a metal organic vapor phase epitaxy (MOVPE) reactor to prepare GaP/Si (111) quasi-substrates . A contamination-free transfer system enables us to assess the MOVPE prepared surfaces with numerous UHV based surface science tools. A dedicated wet-chemical pretreatment is crucial to obtain atomically flat Si(111) surfaces, and high temperature annealing removed all contamination. It is shown that our preparation in a hydrogen ambient results in a monohydride terminated (1x1)-reconstructed Si(111) surface. Since LEED can identify the different GaP(111)A and B surfaces we found that the Si surface termination influences the polarity of GaP films grown on Si(111) substrates.