Wavelength-dependent near-infrared microbolometer for short-wavelength infrared light with gold nanowire grating optical
- PDF / 1,790,389 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 68 Downloads / 178 Views
(0123456789().,-volV)(0123456789(). ,- volV)
TECHNICAL PAPER
Wavelength-dependent near-infrared microbolometer for shortwavelength infrared light with gold nanowire grating optical absorber Tatsuya Tsubota1 • Akio Uesugi1
•
Koji Sugano1
•
Yoshitada Isono1
Received: 26 June 2020 / Accepted: 17 August 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Near-infrared (NIR) imaging has been used for nondestructive and non-contact inspections in various areas, such as food and medicine inspections and medical diagnoses. The short-wavelength infrared light (SWIR) sensor currently used requires a Peltier cooler and a diffraction grating spectroscope owing to its detection principle. Thus, realizing a low-cost and miniaturized SWIR imaging device remains challenging and has limitations for practical applications. In this study, we propose a bolometer-type detector element fabricated using a silicon-on-insulator (SOI) wafer as a low cost and miniaturized SWIR image sensor element. We adopted gold (Au) nanowire grating structures coated with silicon as wavelengthdependent SWIR absorbers and aimed at wavelength-selectivity imaging without using a spectroscope. A device was designed and fabricated with Au nanowire grating structures on a doubly clamped Si beam using microelectromechanical system (MEMS)) technology. The electrical characteristics of the device were measured depending on device temperature and SWIR irradiation intensity. It was found that electrical resistance decreased linearly with increasing device temperature and SWIR irradiation intensity (wavelength at 1530 nm), as semiconductors have negative temperature coefficients of resistance. The results show similar trends from both finite element method (FEM) analysis and theoretical calculation. The resistances at wavelengths ranging from 1530 to 1565 nm at 5 nm increment were evaluated. It was confirmed that absorber-integrated bolometer device enabled wavelength-dependent response of the resistance according to the absorption spectrum.
1 Introduction A near-infrared (NIR) detector that enables nondestructive and non-contact inspection has been recently used in various applications, such as in food (ElMasry et al. 2012; Jiang et al. 2016; Lee et al. 2014; Wu and Sun 2013) and medicine inspections (Andre 2003) and for medical diagnoses (Koizumi et al. 1999; Luo et al. 2011). The detectors currently marketed for short-wavelength infrared light (SWIR, wavelength range: 1–3 lm) are known as photodiodes, which are fabricated from InGaAs (Yuan et al. 2007) or InAs (Marshall et al. 2008) using a photoelectric effect. They have excellent responsiveness and detection sensitivity; however, they require a Peltier cooler to reduce the dark current of the photoelectric effect. Furthermore, they also require a diffraction grating spectroscope for & Koji Sugano [email protected] 1
Department of Mechanical Engineering, Graduate School of Engineering, Kobe University, Kobe, Hyogo 657-8501, Japan
hyperspectral imaging, making their cost re
Data Loading...
