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Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet

Karki Gautam, Laxmi
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1451955209

Abstract Details

2016, Doctor of Philosophy, University of Toledo, Physics.
Optimization of thin film photovoltaics (PV) relies on the capability for characterizing the optoelectronic and structural properties of each layer in the device over large areas and correlating these properties with device performance. This work builds heavily upon that done previously by us, our collaborators, and other researchers. It provides the next step in data analyses, particularly that involving study of films in device configurations maintaining the utmost sensitivity within those same device structures. In this Dissertation, the component layers of thin film hydrogenated silicon (Si:H) solar cells on rigid substrate materials have been studied by real time spectroscopic ellipsometry (RTSE) and ex situ spectroscopic ellipsometry (SE). Growth evolution diagrams has been used to guide deposition of materials with good optoelectronic properties in the actual hydrogenated amorphous silicon (a-Si:H) PV device configuration. The nucleation and evolution of crystallites forming from the amorphous phase were studied using near infrared to ultraviolet spectroscopic ellipsometry in situ, during growth for films prepared as a function of hydrogen to reactive gas flow ratio R = [H2] /{[SiH4] + [Si2H6]. Furthermore, the major challenge in Si:H manufacturing is that quantitative analysis, characterization, and control of the relative nanocrystalline and amorphous volume fractions within mixed-phase films were covered during these studies. In conjunction with higher photon energy measurements, the presence and relative absorption strength of silicon-hydrogen infrared modes were measured by infrared extended ellipsometry measurements to gain some insight into chemical bonding. Structural and optical models have been developed for the back reflector (BR) structure consisting of sputtered undoped zinc oxide (ZnO) on top of silver (Ag) coated glass substrates. Characterization of the free-carrier absorption properties in Ag and the interface formed when Ag is over-coated with ZnO were also studied by infrared extended spectroscopic ellipsometry. Measurements ranging from 0.04 to 5 eV were used to extract layer thicknesses, composition, and optical response in the form of complex dielectric function spectra (e = e1 + ie2) for undoped a-Si:H layers in a substrate n-i-p a-Si:H based PV device structure and on TCO coated glass for p-i-n configurations.
Nikolas J. Podraza (Committee Chair)
Robert W. Collins (Committee Member)
Randall Ellingson (Committee Member)
Song Cheng (Committee Member)
Rashmi Jha (Committee Member)
192 p.
Physics; Plasma Physics; Solid State Physics

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Citations

  • Karki Gautam, L. (2016). Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1451955209

    APA Style (7th edition)

  • Karki Gautam, Laxmi. Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet. 2016. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1451955209.

    MLA Style (8th edition)

  • Karki Gautam, Laxmi. "Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet." Doctoral dissertation, University of Toledo, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1451955209

    Chicago Manual of Style (17th edition)

toledo1451955209
1,327
© 2016, some rights reserved.Creative Commons License Spectroscopic Ellipsometry Studies of Thin Film Si:H Materials in Photovoltaic Applications from Infrared to Ultraviolet by Laxmi Karki Gautam is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Toledo and OhioLINK.