Precise investigation of the light-saturated defect density in amorphous silicon very thin films and solar cells

Kočka, J.; Vaněček, M.; Machacek, P.; Fejfar, A.; Šípek, E.; Ho-The-Ha,; Pelant, I.; Fric, J.; Rosa, J.; Remeš, Z.; Poruba, A.; Konagai, M.; Kusian, W.

doi:10.1109/wcpec.1994.519992

Cited by 1 publication

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“…Thus, at this stage it is not possible to discriminate the dominant transport process in our µc-Si:H material and more extensive measurements will be necessary here. Whereas short-time TOF monitors the transit of the photogenerated carrier package through the layer, the extension of the TOF experiment to a much longer time scale (post-transient TOF [11], [12]) gives information about the density of states (DOS) in the gap. Thereby, electrons and holes which were deep-trapped during transit are thermally reemitted at longer times and their collection becomes a direct fingerprint of the DOS.…”

Section: Electrical Propertiesmentioning

confidence: 99%

Optical and Electrical Properties of Undoped Microcrystalline Silicon Deposited by the VHF-GD with Different Dilutions of Silane in Hydrogen

et al. 1996

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We show that the optical and electrical properties of microcrystalline silicon (µc-Si:H) deposited by the VHF-GD technique at 110 MHz can considerably be tuned by changing the dilution ratio of silane to hydrogen.With increasing silane dilution we observe enhanced optical absorption for energies below 2 eV due to the transition of the material from amorphous / microcrystalline mixture to a pure microcrystalline phase. Simultaneously, the light scattering and the defect absorption increases. Strong dilution also promotes the incorporation of impurities into the material, leading to a pronounced extrinsic behaviour as seen from the decrease of the activiation energy of the electrical conductivity.The electrical properties were investigated in the dark by the Time of Flight technique. We measured drift mobilities at room temperature which slightly increase with dilution, reaching values of 3 cm 2 /Vs for electrons and 1.2 cm 2 /Vs for holes. The ratio between electron and hole drift mobilities is found to be around 2 for all samples studied, similar to that of crystalline silicon.Furthermore, post-transient Time of Flight measurements revealed detrimental electron deep traps in low dilution material.

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Section: Electrical Propertiesmentioning

confidence: 99%