K_P_D_and_D_A_G_Tunable_absorber_Optica_PR.pdf (8.49 MB)
Electrically Tunable Perfect Light Absorbers Utilizing InSb and InAs as epsilon-near-zero semiconductors in Metal-Oxide-Semiconductor Capacitor Architectures
preprintposted on 2023-04-25, 09:41 authored by Don Gregory, Kirtankumar Dixit
The attainment of dynamic tunability in spectrally selective optical absorption has been a longstanding objective in modern optics. Typically, Fabry-Perot resonators comprising metal and semiconductor thin films have been employed for spectrally selective light absorption. In such resonators, the resonance wavelength can be altered via structural modifications. The research has progressed further with the advent of specialized patterning of thin films and the utilization of metasurfaces. Nonetheless, achieving dynamic tuning of the absorption wavelength without altering the geometry of the thin film or without resorting to lithographic fabrication still poses a challenge. In this study, the incorporation of a metal-oxide-semiconductor (MOS) architecture into the Fabry-Perot nanocavity is shown to yield an electrically tunable perfect light absorber within the visible range. Control over light absorption is achieved using n-type doped indium antimonide and n-type doped indium arsenide as semiconductors in a MOS-type structure. These semiconductors offer significant tuning of their optical properties via electrically induced carrier accumulation. The planar structure of the absorber models presented facilitates simple thin-film fabrication. With judicious material selection and appropriate bias voltage, a spectral shift of 47 nm can be achieved within the visible range, thus producing a discernible color change.