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HOT MWIR N + −p HgCdTe photodiode: (a) single detector structure and (b) focal plane array (after Ref. 25). Fig. 13. Hawk image at 210K operating temperature (after Ref. 26).
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At present, uncooled thermal detector focal plane arrays are successfully used in staring thermal imagers. However, the performance of thermal detectors is modest, they suffer from slow response and they are not very useful in applications requiring multispectral detection.
Infrared (IR) photon detectors are typically operated at cryogenic temperat...
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Citations
... Photodetectors are vital in providing information about the light waves and play an essential role in optoelectronics applications, medical devices, and scientific research. Directly or indirectly, photodetectors are used in chemical sensing, environmental monitoring, water purification, flame detection, biological analysis, radiation monitoring, astronomical studies, combustion monitoring, high-speed optical communication, optical switches, thermal imaging, remote sensing, night vision cameras, early missile plume detection, missile launching, space to space communication, information storage technology, aerospace industry, and a variety of other applications [1][2][3][4][5][6][7][8][9][10][11][12][13]. Majority of photodetector-based applications require superior photodetection parameters such as fast response and recovery, high quantum efficiency, ultra-high photosensitivity and detectivity, a broad photon detection limit and ability to operate in harsh environments such as cryogenic and high temperatures. ...
... Development of the high operating temperatures (HOT) photodetectors based on II-VI compounds were specifically focused on HgCdTe solid solutions (Piotrowski et al., 2010;Rogalski et al., 2011). Many new concepts have been implemented and tested to improve their performance (Martyniuk and Rogalski, 2013), (Kalinowski et al., 2019), (Rogalski et al., 2021). ...
... Black dots are measured for detectors with 4−stage TE cooler. Reprinted from(Martyniuk and Rogalski, 2013). Published 2013 by Polish Academy of Sciences (PAN) as open access. ...
This chapter provides data about photoconductive and photovoltaic infrared detectors manufactured from HgCdTe, as well as from the alternative ternary alloy systems, such as HgZnTe and HgMnTe. Their design, performance, advantage, and disadvantages are evaluated and compared. Infrared photon detectors operating in the middle (3–5 μm) and long wavelength (8–14 μm) infrared spectral range require cryogenic cooling to achieve useful performance. Background-limited performance is typically not achieved without significant cooling of the IR photon detectors. At the same time, there are known some concepts of the high operating temperature photon detection proposed and implemented to improve the performance of IR photodetectors near room temperature, which will also be described in this chapter. The characteristics of the photoconductive and photovoltaic infrared detectors, which are produced by the leading manufacturers in this field, are presented in this chapter.
... On this pathway, in 2007 the infrared community proposed the "Rule 07" -a simple relationship representing an empirical fit on the best measured devices [7] -to be the fundamental metric for predicting the dark current in Hg 1−x Cd x Te IR detectors. In a few decades, the outstanding performance of this ternary alloy has enabled the development of four generations of large format IR detectors for imaging in space science, environmental monitoring, diagnostics, surveillance, security, defense, etc. [6], [8]- [13], both for mid-wavelength (MWIR, λ ∈ [3,5] µm) and longwavelength (LWIR, λ ∈ [8,12] µm) infrared bands. Rule 07 was originally intended for P -on-n photodiodes, but soon has been adopted as a reference by technologies other than the HgCdTe-based ones, such as type-II superlattice (T2SL) devices [14]- [16], quantum dot photodetectors [17]- [19], and devices based on two-dimensional materials [20]. 1 The dark current is largely determined by minority carrier lifetimes [8], [21], [22]. ...
The dark current is a fundamental figure of merit to characterize the performance of high-sensitivity, low-noise mid- and far-infrared barrier photodetectors. In the context of HgCdTe barrier photodetectors, the trend is to use very low doping concentrations, in an attempt to minimize recombination processes. In the present work, through TCAD simulations, we delve deeper into the design of low-dark-current
$p$
B
$n$
detectors, showing the possible existence of an optimum doping. This occurrence is investigated and interpreted also by means of closed-form expressions for the lifetimes, emphasizing the role of the interplay between Auger and Shockley-Read-Hall generation processes.
... Such high-temperature detectors are attractive, for instance, in IR spectroscopy applications and gas analyzers. 5 Metasurfaces are planar nanostructured surfaces that have generated much attention recently due to their ability to control the phase, amplitude, and polarization of incident light. [6][7][8][9][10][11] In this work, we developed metasurface lenses (metalenses) which act as metasurface-based optical concentrators when integrated with IR photodetectors to improve their performance. ...
We demonstrate InAsSb-based infrared photodetectors monolithically integrated with metasurface lenses (metalenses) that act as optical concentrators. The metalenses are fabricated on the backside of a gallium antimonide substrate, and the photodetectors are fabricated on the frontside of the same substrate. The metalenses enhance the detector responsivity up to 10-fold and detectors retain the same detectivity at temperatures up to 40 K higher. Detectors integrated with metalenses exhibit detectivities greater than [Formula: see text] at [Formula: see text] μm up to room temperature. Our metasurface-based optical concentrators are based on circular subwavelength nanoposts, which renders their performance polarization independent.
... High-temperature SWIR photodetectors are becoming increasingly significant as sensors in space exploration, night vision, and fire safety [1][2][3][4][5][6]. Due to the synergistic effect of strong electron scattering, low carrier mobility in normal semiconductors, and increased working temperature, the effective photocurrent (I ph ) is quite faint for imaging or target identification [7][8][9][10]. ...
A narrow bandgap of a few layers of platinic disulfide (PtS2) has shown great advantages in large-area array photodetectors for wide spectra photodetection, which is necessary for infrared imaging and infrared sensing under extreme conditions. The photodetection performance of two dimensional materials is highly dependent on the crystalline quality of the film, especially under high operating temperatures. Herein, we developed large area uniform array photodetectors using a chemical vapor deposition grown on PtS2 films for short-wave infrared photodetection at high operating temperature. Due to the high uniformity and crystalline quality of as-grown large area PtS2 films, as-fabricated PtS2 field effect transistors have shown a broadband photo-response from 532 to 2200 nm with a wide working temperature from room temperature to 373 K. The photo-responsivity (R) and specific detectivity (D*) of room temperature and 373 K are about 3.20 A/W and 1.24 × 107 Jones, and 839 mA/W and 6.1 × 106 Jones, at 1550 nm, respectively. Our studies pave the way to create an effective strategy for fabricating large-area short-wave infrared (SWIR) array photodetectors with high operating temperatures using chemical vapor deposition (CVD) grown PtS2 films.
... With high light transmission, the 3-5 μm mid-wave infrared (MWIR) window is favored for its high contrast, superior clear-weather condition, higher penetrability in high humidity, and higher resolution [1,2]. The realization of high operating temperature MWIR photodetectors can eliminate the complex cryogenic cooling system, thereby greatly reducing the volume, weight and power consumption of the infrared detection system [3]. Currently, HgCdTe and InSb are the main players in infrared photodetectors for MWIR spectral band while both of them have some drawbacks [4,5]. ...
Mid-wavelength infrared InAs/InAsSb type-II superlattice p⁺-B-n photodetectors are demonstrated. An AlAsSb/InAsSb superlattice barrier structure is introduced in order to reduce the bias dependency of optical efficiency. The photodetector exhibits a cut-off wavelength of ∼5.0 µm at 150 K. At 150 K and -100 mV applied bias, the photodetector exhibits a dark current density of 1.2×10⁻⁴ A/cm², a quantum efficiency of 29% at peak responsivity (∼4.1 µm), and a specific detectivity of 1.2×10¹¹ cm•Hz1/2/W.
... Mid-wavelength infrared (MWIR) (3-5 µm) detectors are desired for a variety of civilian and military applications such as industrial process monitoring, satellite reconnaissance, and night vision. One critical requirement of the MWIR detectors is the capability of high operating temperature (HOT) operation [1], which reduces the burden of cryogenic cooling significantly and leads to a reduction in size and total cost of the detector system [2]. After decades of development, Sb-based type-II superlattices (T2SLs) has proved to be a viable solution for a variety of infrared detection applications and been considered as a competitive candidate for the HOT MWIR detectors, due to their advantages of band gap tunability, flexibility of band structure engineering [3], large electron effective masses [4], and low Auger recombination [5]. ...
High operating temperature mid-wavelength InAs/GaSb superlattice infrared photodetectors with a single heterojunction structure grown by metal–organic chemical vapor deposition are reported. By inserting a fully-depleted wider-gap barrier layer between the absorber and the p-contact, “diffusion-limited” behavior has been achieved for the heterojunction “PNn” device, in contrast to the conventional pin homojunction device. The PNn device with a 50% cutoff wavelength of 4.5 μm exhibited a dark current of 2.05 × 10−4 A/cm2 and a peak specific detectivity of 1.28 × 1011 cm·Hz·W−1 at 150 K and a reverse bias of −0.1 V.
... 5 A significant way to reduce the SWaP and cost is to develop high operating temperature (HOT) infrared detector technologies (4150 K), where traditional cooling systems, such as liquid-nitrogen Dewar or Stirling coolers, could be removed or replaced by thermoelectric coolers. 6 Two major technologies have been developed for this goal: thermal detectors [7][8][9] and high-temperature photodetectors. Thermal detectors, including microbolometers, 10 and pyroelectric, 11 thermoelectric, 12 thermoresistive 13 and thermomechanical sensors, 14 which rely on IR absorption induced temperature change, have achieved relatively high sensitivity at room temperature or even above room temperature. ...
... However, these uncooled IR thermal detectors generally demonstrate a slow response, and seem to be unsuitable for future IR imaging systems, which are moving toward faster frame rates and multispectral operation. [1][2][3][4][5][6] Simultaneously, more efforts have been spent on developing high HOT infrared photodetectors based on narrow bandgap semiconductors, most notably mercury-cadmium-telluride (MCT), [15][16][17][18][19] In As/GaSb type-II superlattices (T2SLs), 20,21 and inter sub-band based quantum dot infrared photodetectors (QDIPs). [22][23][24][25] However, there is an inherent and reasonable contradiction between high sensitivity and high operating temperature due to the recombination processes of photoexcited carriers, in particular, by Auger recombination. ...
Infrared transparent and conductive coatings (ITCCs) are in significant demand in infrared imaging applications. The combination of high optical transparency in the infrared range (1–12 μm) and high electrical conductivity, however, sets stringent requirements on ITCC materials. A high carrier concentration (> 10²⁰ cm⁻³) employed for high conductivity commonly results in a dramatic drop in the transparency and a distinguishable cutoff blueshift (<2 μm) due to the plasmon effect, which is unable to meet the requirements of infrared optoelectronic devices. To overcome this technical issue, herein, we demonstrate indium-doped cadmium selenide (CdSe:In) ITCC electrodes with high transparency in the infrared range and excellent conductive properties. After optimizing the In/CdSe beam flux ratio and substrate temperature, a champion sheet resistance of 22 Ω per sq was achieved on a BaF2 substrate with an electron concentration of 7.6 × 10¹⁸ cm⁻³ and a mobility of 307 cm² V⁻¹ s⁻¹. The average transmittance is 75% in the 1.0–6.0 μm middle-wavelength infrared (MWIR) range, and more than 50% in the 8–10 μm long-wavelength infrared range (LWIR). By using CdSe:In as an ITCC electrode, we demonstrated an uncooled Au/PbSe/CdSe/CdSe:In/quartz heterojunction photovoltaic detector array. An uncooled PbSe/CdSe PV detector of 50 × 50 μm exhibits an MWIR spectral photo response with a cutoff wavelength of 4.2 μm at room temperature. Under zero-bias photovoltaic mode, the peak responsivity and specific detectivity at room temperature are 0.075 A W⁻¹ and 1.02 × 10⁹ cm Hz1/2 W⁻¹, respectively. Therefore, a CdSe:In ITCCs and PbSe/CdSe heterojunction PV detector provides a technical solution for the manufacturing of low-cost megapixel uncooled lead salt FPA imagers.
... Increasing the operating temperature without detectivity deterioration in so-called high-operating-temperature (HOT) detectors has been the subject of research by many scientific centers, and can be realized in a different ways [3]. Among them, we can list: a suppression of Auger thermal generation in non-equilibrium devices; an optical immersion; multiple passes of IR radiation; magnetoconcentration detectors; Dember detectors; barrier detectors; and alternative materials such as superlattices and cascade infrared detectors [4,5]. In general, there are two main epitaxial growth techniques applied to HgCdTe: liquid-phase epitaxy (LPE); and vapor-phase epitaxy (VPE). ...
This paper presents the current status of medium-wave infrared (MWIR) detectors at the Military University of Technology’s Institute of Applied Physics and VIGO System S.A. The metal–organic chemical vapor deposition (MOCVD) technique is a very convenient tool for the deposition of HgCdTe epilayers, with a wide range of compositions, used for uncooled infrared detectors. Good compositional and thickness uniformity was achieved on epilayers grown on 2-in-diameter, low-cost (100) GaAs wafers. Most growth was performed on substrates, which were misoriented from (100) by between 2° and 4° in order to minimize growth defects. The large lattice mismatch between GaAs and HgCdTe required the usage of a CdTe buffer layer. The CdTe (111) B buffer layer growth was enforced by suitable nucleation procedure, based on (100) GaAs substrate annealing in a Te-rich atmosphere prior to the buffer deposition. Secondary-ion mass spectrometry (SIMS) showed that ethyl iodide (EI) and tris(dimethylamino)arsenic (TDMAAs) were stable donor and acceptor dopants, respectively. Fully doped (111) HgCdTe heterostructures were grown in order to investigate the devices’ performance in the 3–5 µm infrared band. The uniqueness of the presented technology manifests in a lack of the necessity of time-consuming and troublesome ex situ annealing.
... Interestingly, an appreciable photocurrent was observed up to 7 μm even at room temperature ( Figure 3c), although a large number of thermal carriers present at 300 K are expected to annihilate photogenerated carriers through the Auger recombination process, which typically necessitates device cooling. 37,38 The quality of a photodetector is evaluated with specific detectivity, D*, a performance parameter defined by ...
In recent years, there has been increasing interest in leveraging two-dimensional (2D) van der Waals (vdW) crystals for infrared (IR) photodetection, exploiting their unusual optoelectrical properties. Some 2D vdW materials with small band gap energies such as graphene and black phosphorus have been explored as stand-alone IR responsive layers in photodetectors. However, the devices incorporating these IR-sensitive 2D layers often exhibited poor performances owing to their preparation issues such as limited scalability and air instability. Herein, we explored wafer-scale 2D platinum ditelluride (PtTe2) layers for near-to-mid IR photodetection by directly growing them onto silicon (Si) wafers. 2D PtTe2/Si heterojunctions exhibited wavelength- and intensity-dependent high photocurrents in a spectral range of ∼1-7 μm, significantly outperforming stand-alone 2D PtTe2 layers. The observed superiority is attributed to their excellent Schottky junction characteristics accompanying suppressed carrier recombination as well as optical absorbance competition between 2D PtTe2 layers and Si. The direct and scalable growth of 2D PtTe2 layers was further extended to demonstrate mechanically flexible IR photodetectors.
