Analysis and design of InAs nanowire array based ultra broadband perfect absorber

• Published in: RSC advances Vol. 11; no. 59; pp. 37595 - 3763
• Main Authors: Hassan, Mohammad Muntasir, Islam, Fariba, Baten, Md Zunaid, Subrina, Samia
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 23-11-2021; The Royal Society of Chemistry
• Subjects: Absorbers; Absorption spectra; Arrays; Broadband; Chemistry; Circuits; Electromagnetic absorption; Energy harvesting; Incidence angle; Indium arsenides; Mie scattering; Nanowires; Numerical analysis; Photochemistry; Robustness (mathematics); Short circuit currents; Solar energy; Solar power generation; Thin films; Time domain analysis
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d1ra06812a

An ultra-broadband perfect absorber has a wide range of applications which include solar energy harvesting, imaging, photodetection
etc.
In this regard, InAs nanowire (NW) based structure is investigated in this work for achieving an ultra broadband perfect absorber. Finite difference time domain (FDTD) based numerical analysis has been performed to optimize the InAs nanowire based structure to obtain an efficient light absorber by varying different dimensional parameters. Mie theory and guided mode resonance based theoretical analysis is developed to validate the results and to get an insight into the tunability of the nanowire based structure. Moreover, the theoretical analysis elucidates the underlying physics of light absorption in nanowires. To achieve ultra broadband absorption, multi radii InAs nanowire based arrays are investigated and it is found that they exhibit superior performance compared to single radius NW based structures. The computed light absorption efficiency (LAE) and short circuit current density values are enhanced to 97% and 40.15 mA cm
−2
at 10° angle of incidence for the optimized quad radii NW array within the wavelength range of 300 nm to 1000 nm and 300 nm to 1200 nm, respectively. Moreover, the absorption spectra for these structures are polarization independent and exhibit robust performance for varying angle of incidence. In addition, arrangement of the NW array (hexagonal or square) has negligible effect on the absorption spectra. Such ultra-broadband absorption capability of the proposed structure compared to existing works suggests that the InAs nanowire based structure is very promising as light absorber with prospects in the fields of photo detection, solar power generation, perfect cloaking, photochemistry and other thin film photonic devices.
Mie theory and GMR based theoretical framework support the numerical results that resonant wavelength increases with increasing InAs NW diameter. By employing NWs of different diameters in a single array, an ultra-broadband perfect absorber has been achieved.