Physics / Fizik

Permanent URI for this collectionhttps://hdl.handle.net/11147/6

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Author: search.filters.author.Carius, ReinhardPublisher: search.filters.publisher.Elsevier Ltd.

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  • Conference Object
    Citation - WoS: 6
    Citation - Scopus: 9
    Sub-Bandgap Optical Absorption Spectroscopy of Hydrogenated Microcrystalline Silicon Thin Films Prepared Using Hot-Wire Cvd (cat-Cvd) Process
    (Elsevier Ltd., 2006) Göktaş, Oktay; Işık, Nebile; Okur, Salih; Güneş, Mehmet; Carius, Reinhard; Klomfaß, Josef; Finger, Friedhelm
    Hydrogenated microcrystalline silicon (μc-Si:H) thin films with different silane concentration (SC) have been prepared using the HW-CVD technique. Dual beam photoconductivity (DBP), photothermal deflection spectroscopy (PDS), and transmission measurements have been used to investigate the optical properties of the μc-Si:H films. Two different sub-bandgap absorption, α(hν), methods have been applied and analyzed to obtain a better insight into the electronic states involved. A good agreement has been obtained in the absorption spectrum obtained from the PDS and DBP measurements at energies above the bandgap. Differences between PDS and DBP spectra exist below the bandgap energy where DBP spectra always give lower α(hν) values and show a dependence on the SC. For some films, differences exist in the α(hν) spectra when the DBP measurements are carried out through the film and substrate side. In addition, for some films, there remains fringe pattern left on the spectrum after the calculation of the fringe-free absorption spectrum, which indicates structural inhomogeneities present throughout the film.
  • Conference Object
    Citation - WoS: 8
    Citation - Scopus: 9
    Diffusion Length Measurements of Microcrystalline Silicon Thin Films Prepared by Hot-wire/Catalytic Chemical Vapor Deposition (hwcvd)
    (Elsevier Ltd., 2006) Okur, Salih; Güneş, Mehmet; Finger, Friedhelm; Carius, Reinhard
    Hydrogenated microcrystalline silicon (μc-Si:H) films prepared by using the hot-wire/catalytic chemical vapor deposition (HWCVD) technique at low substrate temperatures between 185 °C and 220 °C with different silane concentrations (SC) were investigated using steady-state photocarrier grating (SSPG) and the steady-state photoconductivity methods (SSPC). Crystalline volume fractions (IC RS) obtained from Raman spectroscopy change from 0.22 to 0.77. The diffusion length (LD) is measured at generation rates between G = 1019 and 1021 cm- 3 s- 1. LD changes from 27 nm to 270 nm, with maximum values around SC = 5%. The dependence of LD on SC is similar to that observed for similar quality microcrystalline silicon films prepared using the VHF-PECVD technique. The grating quality factor, γ0, drops from about 0.9 to 0.5 after transition to the microcrystalline regime as indication of scattering from surface patterns.