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Title: Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO{sub 2} films

Abstract

Infrared radiation is used to radiatively transfer heat to a nanometric power generator (NPG) device with a thermoelectric Nb-doped TiO{sub 2} film deposited by atomic layer deposition (ALD) as the active element, onto a borosilicate glass substrate. The linear rise of the produced voltage with respect to the temperature difference between the “hot” and “cold” junctions, typical of the Seebeck effect, is missing. The discovery of the violation of the Seebeck effect in NPG devices combined with the ability of ALD to tune thermoelectric thin film properties could be exploited to increase the efficiency of these devices for energy harvesting purposes.

Authors:
; ; ;  [1]; ;  [2]
  1. Department of Physics and Astronomy, James Madison University, 901 Carrier Drive, Harrisonburg, Virginia 22807 (United States)
  2. Department of Chemistry, Aalto University, P.O. Box 16100, Aalto, 00076 Finland (Finland)
Publication Date:
OSTI Identifier:
22392097
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 33; Journal Issue: 1; Other Information: (c) 2014 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; BOROSILICATE GLASS; DEPOSITION; DEPOSITS; DOPED MATERIALS; EFFICIENCY; ELECTRIC POTENTIAL; HEAT; INFRARED RADIATION; LAYERS; NANOSTRUCTURES; RADIANT HEAT TRANSFER; SEEBECK EFFECT; THIN FILMS; TITANIUM OXIDES

Citation Formats

Mann, Harkirat S., Lang, Brian N., Schwab, Yosyp, Scarel, Giovanna, E-mail: scarelgx@jmu.edu, Niemelä, Janne-Petteri, and Karppinen, Maarit. Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO{sub 2} films. United States: N. p., 2015. Web. doi:10.1116/1.4901457.
Mann, Harkirat S., Lang, Brian N., Schwab, Yosyp, Scarel, Giovanna, E-mail: scarelgx@jmu.edu, Niemelä, Janne-Petteri, & Karppinen, Maarit. Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO{sub 2} films. United States. doi:10.1116/1.4901457.
Mann, Harkirat S., Lang, Brian N., Schwab, Yosyp, Scarel, Giovanna, E-mail: scarelgx@jmu.edu, Niemelä, Janne-Petteri, and Karppinen, Maarit. Thu . "Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO{sub 2} films". United States. doi:10.1116/1.4901457.
@article{osti_22392097,
title = {Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO{sub 2} films},
author = {Mann, Harkirat S. and Lang, Brian N. and Schwab, Yosyp and Scarel, Giovanna, E-mail: scarelgx@jmu.edu and Niemelä, Janne-Petteri and Karppinen, Maarit},
abstractNote = {Infrared radiation is used to radiatively transfer heat to a nanometric power generator (NPG) device with a thermoelectric Nb-doped TiO{sub 2} film deposited by atomic layer deposition (ALD) as the active element, onto a borosilicate glass substrate. The linear rise of the produced voltage with respect to the temperature difference between the “hot” and “cold” junctions, typical of the Seebeck effect, is missing. The discovery of the violation of the Seebeck effect in NPG devices combined with the ability of ALD to tune thermoelectric thin film properties could be exploited to increase the efficiency of these devices for energy harvesting purposes.},
doi = {10.1116/1.4901457},
journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
number = 1,
volume = 33,
place = {United States},
year = {Thu Jan 15 00:00:00 EST 2015},
month = {Thu Jan 15 00:00:00 EST 2015}
}
  • Undoped and nitrogen doped TiO{sub 2} thin films were deposited by atomic layer deposition on planar substrates. Deposition on 3D-architecture substrates made of metallic foams was also investigated to propose architectured photovoltaic stack fabrication. All the films were deposited at 265 °C and nitrogen incorporation was achieved by using titanium isopropoxide, NH{sub 3} and/or N{sub 2}O as precursors. The maximum nitrogen incorporation level obtained in this study was 2.9 at. %, resulting in films exhibiting a resistivity of 115 Ω cm (+/−10 Ω cm) combined with an average total transmittance of 60% in the 400–1000 nm wavelength range. Eventually, TiO{sub 2} thin filmsmore » were deposited on the 3D metallic foam template.« less
  • Nb-doped anatase TiO{sub 2} films were deposited on unheated glass by dc magnetron sputtering using slightly reduced Nb-doped TiO{sub 2-x} targets (Nb concentration: 3.7 and 9.5 at. %) with various hydrogen or oxygen flow ratios. After postannealing in a vacuum (6x10{sup -4} Pa) at 500 deg. C for 1 h, both films were crystallized into the polycrystalline anatase TiO{sub 2} structure. The resistivity decreased from 1.6x10{sup -3} to 6.3x10{sup -4} {Omega} cm with increasing Nb concentration from 2.8 to 8.0 at. %, where the carrier density increased from 5.4x10{sup 20} to 2.0x10{sup 21} cm{sup -3} and the Hall mobility wasmore » almost constant at 5-7 cm{sup 2} V{sup -1} s{sup -1}. The films exhibited a high transparency of over 60%-80% in the visible region.« less
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  • Highlights: • TiO{sub 2}:Nb (1.2 at.%) multilayer films were deposited by sol–gel method on glass and Si. • 5 and 10 layers TiO{sub 2}:Nb films crystallize only in the anatase phase. • E{sub g} values are within 3.24–3.32 eV showing a decrease with increasing the layer number. • The specific resistivity, effective donor and sheet energy densities were obtained. • Nb donor compensation by acceptor levels in TiO{sub 2}:Nb film was suggested. - Abstract: Thin films of 5 and 10-layered sol–gel TiO{sub 2} were doped with 1.2 at.% Nb and their structural, optical and electrical properties were investigated. The filmsmore » crystallized only in anatase phase, as evidenced by X-ray diffraction and selected area electron diffraction analyses. High resolution transmission electron microscopy revealed nanosized crystallites with amorphous boundaries. Current-voltage measurements on metal-TiO{sub 2}–Si structures showed the formation of n{sup +}–n heterojunction at the TiO{sub 2}–Si interface with a rectification ratio of 10{sup 4}. The effective donor density varies between 10{sup 16} and 10{sup 17} cm{sup −3}, depending on film thickness. The sheet energy densities under forward and reverse bias are in the order of 10{sup 12} and 10{sup 10} cm{sup −2} eV{sup −1}, respectively. These values and the high specific resistivity (10{sup 4} Ω cm) support the existence of compensating acceptor levels in these films. It was established that the conduction mechanism is based on space charge limited current via deep levels with different energy positions in the band gap.« less
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