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Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices

Optimization of thin film photovoltaics (PV) relies on characterizing the optoelectronic and structural properties of each layer and correlating these properties with device performance. Growth evolution diagrams have been used to guide production of materials with good optoelectronic properties in...

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Autores principales: Karki Gautam, Laxmi, Junda, Maxwell M., Haneef, Hamna F., Collins, Robert W., Podraza, Nikolas J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5456701/
https://www.ncbi.nlm.nih.gov/pubmed/28773255
http://dx.doi.org/10.3390/ma9030128
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author Karki Gautam, Laxmi
Junda, Maxwell M.
Haneef, Hamna F.
Collins, Robert W.
Podraza, Nikolas J.
author_facet Karki Gautam, Laxmi
Junda, Maxwell M.
Haneef, Hamna F.
Collins, Robert W.
Podraza, Nikolas J.
author_sort Karki Gautam, Laxmi
collection PubMed
description Optimization of thin film photovoltaics (PV) relies on characterizing the optoelectronic and structural properties of each layer and correlating these properties with device performance. Growth evolution diagrams have been used to guide production of materials with good optoelectronic properties in the full hydrogenated amorphous silicon (a-Si:H) PV device configuration. The nucleation and evolution of crystallites forming from the amorphous phase were studied using in situ near-infrared to ultraviolet spectroscopic ellipsometry during growth of films prepared as a function of hydrogen to reactive gas flow ratio R = [H(2)]/[SiH(4)]. 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 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 ZnO + Ag interface as well as phonon modes in ZnO were also studied by 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 (ε = ε(1) + iε(2)) for Ag, ZnO, the ZnO + Ag interface, and undoped a-Si:H layer in a substrate n-i-p a-Si:H based PV device structure.
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spelling pubmed-54567012017-07-28 Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices Karki Gautam, Laxmi Junda, Maxwell M. Haneef, Hamna F. Collins, Robert W. Podraza, Nikolas J. Materials (Basel) Article Optimization of thin film photovoltaics (PV) relies on characterizing the optoelectronic and structural properties of each layer and correlating these properties with device performance. Growth evolution diagrams have been used to guide production of materials with good optoelectronic properties in the full hydrogenated amorphous silicon (a-Si:H) PV device configuration. The nucleation and evolution of crystallites forming from the amorphous phase were studied using in situ near-infrared to ultraviolet spectroscopic ellipsometry during growth of films prepared as a function of hydrogen to reactive gas flow ratio R = [H(2)]/[SiH(4)]. 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 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 ZnO + Ag interface as well as phonon modes in ZnO were also studied by 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 (ε = ε(1) + iε(2)) for Ag, ZnO, the ZnO + Ag interface, and undoped a-Si:H layer in a substrate n-i-p a-Si:H based PV device structure. MDPI 2016-02-25 /pmc/articles/PMC5456701/ /pubmed/28773255 http://dx.doi.org/10.3390/ma9030128 Text en © 2016 by the authors; Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Karki Gautam, Laxmi
Junda, Maxwell M.
Haneef, Hamna F.
Collins, Robert W.
Podraza, Nikolas J.
Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices
title Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices
title_full Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices
title_fullStr Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices
title_full_unstemmed Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices
title_short Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon Based Photovoltaic Devices
title_sort spectroscopic ellipsometry studies of n-i-p hydrogenated amorphous silicon based photovoltaic devices
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5456701/
https://www.ncbi.nlm.nih.gov/pubmed/28773255
http://dx.doi.org/10.3390/ma9030128
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