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HL: Fachverband Halbleiterphysik
HL 82: Poster: Surfaces, interfaces and heterostructures (with O)
HL 82.2: Poster
Mittwoch, 2. April 2014, 17:00–20:00, P1
Defect states and band bending effects at c-Si(111)/a-SiN:H interfaces — •Leif Eric Hintzsche1, Changming Fang1, Gerald Jordan1, Martijn Marsman1, Machteld Lamers2, Arthur Weeber2, and Georg Kresse1 — 1University of Vienna, Faculty of Physics and Center for Computational Materials Science, Sensengasse 8/12, A-1090 Vienna, Austria — 2ECN Solar Energy, P.O. Box 1, 1755 ZG Petten, Netherlands
High performance solar cells based on crystalline silicon (c-Si) still play a major role in the photovoltaic market, and amorphous silicon nitride (a-SiN:H) often serves as anti-reflection coating (ARC) and passivation layer on top of those cells. The passivation properties are, thereby, strongly influenced by electronic defect states at the interface. In present study, these defects have been investigated by using ab intio molecular dynamics. We prepared 900 different c-Si/a-SiN:H structures and classified the most important defect types at the interface. Afterwards, we examined their energetic and spacial localization, and their band structure. We generally find higher defect concentrations at the interface, which are dominated by occupied, localized states in the a-SiN part and unoccupied, delocalized states in the c-Si part. While the former are mainly localized at under-coordinated Si atoms, the latter have rather inherited the character of the c-Si conduction band. We argue that this difference is a strong evidence for the band bending effect at the c-Si/a-SiN:H heterojunction.