Luk, Ting S;
Xu, Guangping;
Ross, Willard;
Nogan, John N;
Scott, Ethan A;
Ivanov, Sergei;
Niculescu, Oana;
... Harris, C Thomas; + view all
(2022)
Maximal absorption in ultrathin TiN films for microbolometer applications.
Applied Physics Letters
, 121
(23)
, Article 234101. 10.1063/5.0123671.
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Abstract
Ultrathin light absorbers present a viable route toward improving the specific detectivity and response time of microbolometers. However, for an ultrathin film to absorb light efficiently, the dielectric function of the film and its thickness must satisfy strict requirements. We experimentally demonstrate an average absorptance of 48% ± 2.5% in the 8–13 μm (769–1250 cm−1) spectral range for 10 nm thick titanium nitride (TiN), a value bordering on the 50% fundamental absorptance limit for a suspended thin film. The heat capacity per unit area of this absorber is only 1.2 × 10−6 J/K/cm2, which is beneficial for improving the response time of a microfabricated bolometer. We also show that a sufficient condition for reaching maximal absorption in an ultrathin film is that ε″ ≫ |ε′|.
| Type: | Article |
|---|---|
| Title: | Maximal absorption in ultrathin TiN films for microbolometer applications |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1063/5.0123671 |
| Publisher version: | https://doi.org/10.1063/5.0123671 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10161846 |
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