Scaling infrared detectors—status and outlook

Abstract

The predicted “Law 19” benchmark for HgCdTe photodiode performance established in 2019 is a milestone in the development of infrared detectors and make the dream of Elliott and colleagues, who in 1999 wrote that there is no fundamental obstacle to obtaining room temperature operation of photon detectors at room temperature with background-limited performance even in reduced fields of view [C.T. Elliott et al., Appl. Phys. Lett. 74(9), 2881 (1999)]. This circumstance will make it possible to achieve in the near future the room-temperature infrared (IR) arrays operation with high pixel density (small pixels) fully compatible with the background and diffraction-limited performance resulting from the system optics. The advent of smaller pixels also results in superior spatial and temperature resolutions of imaging systems. In megapixel imaging systems, the pixel dimension plays a crucial role in determining critical system attributes such as system size, weight, and power consumption (SWaP). In the paper, the physical limitations of pixel size related to the aperture of the optics, which in turn is wavelength dependent, are described. Since the critical parameter of small pixels is quantum efficiency, more attention has been paid to enhancing the coupling of radiation to the detector. Then, the evaluation for assessing the figure-of-merit of different material systems (especially short wavelength IR colloidal quantum dots, both medium and long wavelength IR novel III-V material systems) relative to bulk HgCdTe alloys is considered. Of the various thermal detectors, particular attention has been focused on bolometer arrays due to their largest share of the global commercial market. Also key challenges in realizing ultimate pixel dimensions in focal plane arrays (FPAs) design are presented for different material systems including dark current, pixel hybridization, pixel delineation, and unit cell readout capacity.

Monolayer Graphene Terahertz Detector Integrated with Artificial Microstructure

“…As a critical component in the THz field, the challenge of efficient photodetection and fast response remains [ 7 ]. Currently, several commercial detectors are available, including GaN detectors, GaAs-based detectors, and thermal detectors, yet their response times being in the millisecond range limits their application in the field of THz technology [ 8 , 9 , 10 , 11 , 12 , 13 ].…”

Capabilities of scaled microbolometers for uncooled thermal imaging below 10µm pixel pitch

“…Following the trend of cooled thermal imager technologies, uncooled thermal imagers also aim for smaller pixel pitches to enable higher optical resolutions. [4][5][6] In consequence, this trend led to the development of uncooled thermal imagers based on microbolometers demonstrating their electro-optical functionality down to pixel sizes of only 6 µm in case of Fraunhofer IMS's scalable nanotube-microbolometer technology [1][2][3] and in parallel, to further uncooled thermal imagers with pixel pitches below 10 µm manufactured by InfiRay 7 and Lynred 8 . Since the detector size of those microbolometers continously approaches the optical detection limit in the long wavelength infrared (LWIR), 9 it seems to be only a matter of time when this physical limit will finally be reached.…”

Carbon Nanotube-Based Uncooled Bolometers: Advances and Progress

“…are too various BM design and fabrication considerations. Further details of these fabrication techniques can be found in the recent review articles and book chapter; − readers are strongly suggested to refer them for a more comprehensive understanding.…”