HOPPING TRANSPORT IN n-a-Si:H EMITTERS OF SILICON HETEROSTRUCTURE SOLAR CELLS

Hopping transport through heterostructure solar cells based on B-doped crystalline silicon wafers with highly P-doped hydrogenated amorphous silicon emitters with different thicknesses is investigated at T = 10 K with pulsed electrically detected magnetic resonance. The measurements show that transport is dominated by conduction band tail states (g ≈ 2.0046) with a distribution of their mutual coupling strength. The signal intensity correlates to the sample thickness and the g-factors do not exhibit an anisotropy which suggests that transport is still dominated by bulk properties of amorphous silicon. In addition, two broad P-donor hyperfine satellites can be detected. Influences of interface defects such as Pb-like states known from silicon dioxide interfaces are either suppressed by the high Fermi-energy at the interface or not present. __________________________________________________________________________________________________________________________________ PACS: 72.20.Ee Mobility edges; hopping transport 72.25.Dc Spin polarized transport in semiconductors 72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping 76.90.+d Other topics in magnetic resonances and relaxations