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Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered thin films.

Kocer H, Butun S, Palacios E, Liu Z, Tongay S, Fu D, Wang K, Wu J, Aydin K - Sci Rep (2015)

Bottom Line: Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition.Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20 nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum.Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA.

ABSTRACT
Plasmonic and metamaterial based nano/micro-structured materials enable spectrally selective resonant absorption, where the resonant bandwidth and absorption intensity can be engineered by controlling the size and geometry of nanostructures. Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition. Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20 nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum. Our numerical and experimental results indicate that the bandwidth of the absorption bands can be controlled by changing the dielectric spacer layer thickness. Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing.

No MeSH data available.


Experimental setup and BBA device designs.PMMA spacer layer (tPMMA = 500 nm and 700 nm) and 60 nm gold cap layer was deposited on VO2 on sapphire substrate. The device is mounted upside down inside an infrared microscope and illuminated at normal incidence using a mid-IR source. (a) VO2 is set to insulator phase (i-VO2) by adjusting temperature of the controlled plate at 23 °C. (b) VO2 is set to metallic phase (m-VO2) by adjusting temperature of the controlled plate at 123 °C. (The thermometer illustration is drawn by S.B.)
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f1: Experimental setup and BBA device designs.PMMA spacer layer (tPMMA = 500 nm and 700 nm) and 60 nm gold cap layer was deposited on VO2 on sapphire substrate. The device is mounted upside down inside an infrared microscope and illuminated at normal incidence using a mid-IR source. (a) VO2 is set to insulator phase (i-VO2) by adjusting temperature of the controlled plate at 23 °C. (b) VO2 is set to metallic phase (m-VO2) by adjusting temperature of the controlled plate at 123 °C. (The thermometer illustration is drawn by S.B.)

Mentions: Tunable BBA device designs presented here consist of three layer stack of VO2, dielectric and Au continuous films. Poly(methyl methacrylate) (PMMA) is used as a spacer between 20 nm VO2 film and a lossy 60 nm thick Au layer. Figure 1(a,b) show schematics of insulating and metallic phases of VO2 in connection with temperature, respectively. IR illumination is sent from the sapphire side. Au layer is placed on a temperature controlled plate, which is mounted inside an IR microscope (Bruker Hyperion 2000). Spectral reflection measurements were carried out using an IR microscope which is coupled to a Fourier transform infrared (FTIR) spectrometer (Bruker Vertex 70) equipped with liquid nitrogen cooled mercury cadmium telluride (HgCdTe) detector. Two different BBAs were designed with the PMMA thicknesses of 500 nm and 700 nm. VO2 film behaves like an insulator at room temperature while it is fully metallic above the transition temperature (123 °C in our study). Therefore, we will refer these two different device conditions as “i-VO2” and “m-VO2”. Temperatures of these BBAs were set to room (23 °C) and hot (123 °C) for two different cases.


Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered thin films.

Kocer H, Butun S, Palacios E, Liu Z, Tongay S, Fu D, Wang K, Wu J, Aydin K - Sci Rep (2015)

Experimental setup and BBA device designs.PMMA spacer layer (tPMMA = 500 nm and 700 nm) and 60 nm gold cap layer was deposited on VO2 on sapphire substrate. The device is mounted upside down inside an infrared microscope and illuminated at normal incidence using a mid-IR source. (a) VO2 is set to insulator phase (i-VO2) by adjusting temperature of the controlled plate at 23 °C. (b) VO2 is set to metallic phase (m-VO2) by adjusting temperature of the controlled plate at 123 °C. (The thermometer illustration is drawn by S.B.)
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543955&req=5

f1: Experimental setup and BBA device designs.PMMA spacer layer (tPMMA = 500 nm and 700 nm) and 60 nm gold cap layer was deposited on VO2 on sapphire substrate. The device is mounted upside down inside an infrared microscope and illuminated at normal incidence using a mid-IR source. (a) VO2 is set to insulator phase (i-VO2) by adjusting temperature of the controlled plate at 23 °C. (b) VO2 is set to metallic phase (m-VO2) by adjusting temperature of the controlled plate at 123 °C. (The thermometer illustration is drawn by S.B.)
Mentions: Tunable BBA device designs presented here consist of three layer stack of VO2, dielectric and Au continuous films. Poly(methyl methacrylate) (PMMA) is used as a spacer between 20 nm VO2 film and a lossy 60 nm thick Au layer. Figure 1(a,b) show schematics of insulating and metallic phases of VO2 in connection with temperature, respectively. IR illumination is sent from the sapphire side. Au layer is placed on a temperature controlled plate, which is mounted inside an IR microscope (Bruker Hyperion 2000). Spectral reflection measurements were carried out using an IR microscope which is coupled to a Fourier transform infrared (FTIR) spectrometer (Bruker Vertex 70) equipped with liquid nitrogen cooled mercury cadmium telluride (HgCdTe) detector. Two different BBAs were designed with the PMMA thicknesses of 500 nm and 700 nm. VO2 film behaves like an insulator at room temperature while it is fully metallic above the transition temperature (123 °C in our study). Therefore, we will refer these two different device conditions as “i-VO2” and “m-VO2”. Temperatures of these BBAs were set to room (23 °C) and hot (123 °C) for two different cases.

Bottom Line: Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition.Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20 nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum.Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA.

ABSTRACT
Plasmonic and metamaterial based nano/micro-structured materials enable spectrally selective resonant absorption, where the resonant bandwidth and absorption intensity can be engineered by controlling the size and geometry of nanostructures. Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition. Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20 nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum. Our numerical and experimental results indicate that the bandwidth of the absorption bands can be controlled by changing the dielectric spacer layer thickness. Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing.

No MeSH data available.