Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 30: Photovoltaik II

HL 30.4: Vortrag

Mittwoch, 10. März 2004, 16:00–16:15, H14

Quantitative Photoluminescence In a-Si:H/c-Si Heterostructures- Determination Of Quasi-Fermi Level Splitting — •Saioa Tardon, Rudolf Brüggemann, and Gottfried H. Bauer — Institute of Physics, Carl von Ossietzky University Oldenburg

Photoluminescence is broadly applied for probing the electronic structure of materials and is mostly recorded in arbitrary units, whereas absolute luminescence additionally yields the information on the quality of the photoexcited state of matter. We consider the experimentally detected luminescence as spectrally selective radiation from matter in thermal non-equilibrium and describe the emitted spectral photon flux by Planck’s generalised law. Via this approach the luminescence flux from semiconductors is related to the chemical potential of the electron-hole-ensemble/splitting of quasi-Fermi levels and also to the concentrations of electrons/holes in the initial/final states of the radiative transitions. We have applied these diagnostics to a-Si:H/c-Si heterostructures with different emitter a-Si:H-layers and with various methods of c-Si surface passivation. The magnitude of the quasi-Fermi level splitting will be used to predict the maximum achievable open circuit voltage in the final devices.