Abstract
In 1934, Wilhelm Woltersdorff demonstrated that the absorption of light in an ultrathin, freestanding film is fundamentally limited to 50%. He concluded that reaching this limit would require a film with a real-valued sheet resistance that is exactly equal to R = η/2 ≈ 188.5Ω/, where η=μ0/ϵ0 is the impedance of free space. This condition can be closely approximated over a wide frequency range in metals that feature a large imaginary relative permittivity ϵr″, that is, a real-valued conductivity σ = ϵ0ϵr″ω. A thin, continuous sheet of semiconductor material does not facilitate such strong absorption as its complex-valued permittivity with both large real and imaginary components preclude effective impedance matching. In this work, we show how a semiconductor metafilm constructed from optically resonant semiconductor nanostructures can be created whose optical response mimics that of a metallic sheet. For this reason, the fundamental absorption limit mentioned above can also be reached with semiconductor materials, opening up new opportunities for the design of ultrathin optoelectronic and light harvesting devices.
| Original language | English |
|---|---|
| Pages (from-to) | 3801-3808 |
| Number of pages | 8 |
| Journal | Nano Letters |
| Volume | 16 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2016 Jun 8 |
| Externally published | Yes |
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Keywords
- germanium nanobeam
- light absorption
- Metafilm
- Mie resonance
- semiconductor nanoantenna
ASJC Scopus subject areas
- Bioengineering
- Chemistry(all)
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering
Cite this
Superabsorbing, artificial metal films constructed from semiconductor nanoantennas. / Kim, Soo Jin; Park, Junghyun; Esfandyarpour, Majid; Pecora, Emanuele F.; Kik, Pieter G.; Brongersma, Mark L.
In: Nano Letters, Vol. 16, No. 6, 08.06.2016, p. 3801-3808.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Superabsorbing, artificial metal films constructed from semiconductor nanoantennas
AU - Kim, Soo Jin
AU - Park, Junghyun
AU - Esfandyarpour, Majid
AU - Pecora, Emanuele F.
AU - Kik, Pieter G.
AU - Brongersma, Mark L.
PY - 2016/6/8
Y1 - 2016/6/8
N2 - In 1934, Wilhelm Woltersdorff demonstrated that the absorption of light in an ultrathin, freestanding film is fundamentally limited to 50%. He concluded that reaching this limit would require a film with a real-valued sheet resistance that is exactly equal to R = η/2 ≈ 188.5Ω/, where η=μ0/ϵ0 is the impedance of free space. This condition can be closely approximated over a wide frequency range in metals that feature a large imaginary relative permittivity ϵr″, that is, a real-valued conductivity σ = ϵ0ϵr″ω. A thin, continuous sheet of semiconductor material does not facilitate such strong absorption as its complex-valued permittivity with both large real and imaginary components preclude effective impedance matching. In this work, we show how a semiconductor metafilm constructed from optically resonant semiconductor nanostructures can be created whose optical response mimics that of a metallic sheet. For this reason, the fundamental absorption limit mentioned above can also be reached with semiconductor materials, opening up new opportunities for the design of ultrathin optoelectronic and light harvesting devices.
AB - In 1934, Wilhelm Woltersdorff demonstrated that the absorption of light in an ultrathin, freestanding film is fundamentally limited to 50%. He concluded that reaching this limit would require a film with a real-valued sheet resistance that is exactly equal to R = η/2 ≈ 188.5Ω/, where η=μ0/ϵ0 is the impedance of free space. This condition can be closely approximated over a wide frequency range in metals that feature a large imaginary relative permittivity ϵr″, that is, a real-valued conductivity σ = ϵ0ϵr″ω. A thin, continuous sheet of semiconductor material does not facilitate such strong absorption as its complex-valued permittivity with both large real and imaginary components preclude effective impedance matching. In this work, we show how a semiconductor metafilm constructed from optically resonant semiconductor nanostructures can be created whose optical response mimics that of a metallic sheet. For this reason, the fundamental absorption limit mentioned above can also be reached with semiconductor materials, opening up new opportunities for the design of ultrathin optoelectronic and light harvesting devices.
KW - germanium nanobeam
KW - light absorption
KW - Metafilm
KW - Mie resonance
KW - semiconductor nanoantenna
UR - http://www.scopus.com/inward/record.url?scp=84974574089&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84974574089&partnerID=8YFLogxK
U2 - 10.1021/acs.nanolett.6b01198
DO - 10.1021/acs.nanolett.6b01198
M3 - Article
AN - SCOPUS:84974574089
VL - 16
SP - 3801
EP - 3808
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 6
ER -