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Two-Dimensional Materials in Photoconductive Detectors
Published in Sam Zhang, Materials for Devices, 2023
Yu Duan, Shuanglong Feng, Sam Zhang
Photodetectors play an essential role in the photoelectric system. Photodetectors convert light signals into electrical signals, which are processed by electronic circuits to realize light detection function.[1–3] Nowadays, photodetectors have been widely used in photoelectric display, imaging, environmental monitoring, optical communication, military, safety inspection, biomedicine, and many other fields.[4–7] According to the different detection bands, their functions are also different. For instance, deep ultraviolet light detectors are used for ultraviolet lithography and living cell detection. Visible range detectors are used in digital cameras and visual imaging, and infrared detectors are used in night vision, optical communication, and atmospheric quality inspection. Since the discovery of the photoelectric effect in 1887,[8] scientists have devoted themselves to exploring the interaction between light and semiconductor materials, which has laid the foundation for many theories of optoelectronic systems and become the key to modern industrial and scientific applications.
Introduction
Published in Antoni Rogalski, 2D Materials for Infrared and Terahertz Detectors, 2020
The early history of IR was reviewed about 60 years ago in two well-known monographs [2,3]. Much historical information can be also found in more recently published papers [4,5]. The initial infrared detectors were based on the class of thermal detectors: thermometers, thermocouples, and bolometers [6]. In 1821, T.J. Seebeck discovered the thermoelectric effect, and soon afterward, in 1829, L. Nobili created the first thermocouple. In 1833, M. Melloni modified the thermocouple and used bismuth and antimony for its design [7]. Then, in 1835, Nobili, together with Melloni, constructed a thermopile capable of sensing a person 10 m away. The third type of thermal detector, the bolometer/thermistor, was invented by S.P. Langley in 1878. By 1900, his bolometer was 400 times more sensitive than his first efforts, and his latest bolometer could detect the heat from a cow at a distance of ¼ mile [8].
CVD of superlattice films and their applications
Published in Kwang Leong Choy, Chemical Vapour Deposition (CVD), 2019
Infrared detectors are required for applications in defence, night vision, astronomy, thermal mapping, gas-sensing, etc. Quantum-well ISB photodetectors (QWIPs) are designed so that the energy separation of the confined levels is matched to the chosen wavelength. A major advantage of QWIPs over the conventional approach employing narrow-gap semiconductors is the use of mature GaAs-based technologies.
Thermal history analysis on a hot surface using temperature indicating paints
Published in International Journal of Ambient Energy, 2022
P. L. Rupesh, M. Arulprakasajothi
The infrared energy coming from an object is focused on an infrared detector. The detector sends the information to sensor electronics to process the image. The electronics translates the data coming from the detector into an image that can be viewed in the viewfinder or on a standard video monitor or LCD screen. Infrared thermography is a method of transforming an infrared image into a radiometric one which allows temperature values to be read from the image. To read the correct temperature, one important thing needs to be taken into account: emissivity. Emissivity is the efficiency with which an object emits infrared radiation. This is highly dependent on the material properties. It’s important to set the camera to the correct emissivity to get the exact temperatures. It is extremely important to set the camera to correct emissivity for the desired material as most of the emissivity data are present in the camera itself or an emissivity table could be used. Figure 8 shows the thermal image covering the throat region, indicating a temperature above 400°C. Figure 9 shows the thermal image covering the right and left end region, indicating a temperature of 277° and 240°C, respectively.
Structural transition and thermo-physical study of quaternary (Se80Te20)94-x Ge6Pb x (0 ≤ x ≤ 12) alloys
Published in Phase Transitions, 2022
Priyanka Vashist, Balbir Singh Patial, Suresh Bhardwaj, A.M. Awasthi, S.K. Tripathi, Nagesh Thakur
The unique property of the phase transition of Se has made it widely used in commercial applications [14]. Addition of Te to pure Se circumvents the problem of low photosensitivity and aging effects making Se-Te-based chalcogenides most popular among all the other chalcogenide systems due to their extensive applications owing to their unique structural, dielectric and non-linear properties [15,16]. Ge when added to Se-Te alloy creates configurational and compositional disorder in the binary alloy. Infrared detectors are important for the surface analysis by thermography, night vision and weather forecasting. Lead chalcogenides have proven to be excellent alternative to mid-IR detection systems like micro-bolometers and quantum well infrared photodetectors. The Pb-based photodetection systems do not require cooling for operation and have shown high-speed photodetection capabilities like their quantum well infrared counterparts [17]. Pb additive chalcogenide system has been a strong candidate of low cost and efficient mid-infrared detector as it can be used with numerous substrates. This has brought a revolution in integrated optoelectronics as on chip detection systems manage to give excellent signal to noise ratio [18]. Moreover, Pb-Te- and Pb-Se-based alloys are used in mid-temperature (∼500–600°C) thermoelectric [19,20]. Consequently, the choice of Pb dopant has been made in the present paper because it opens numerous potential applications varying from infrared sensors, solar energy conversion devices, thermoelectric, photodetectors, non-linear optical devices and lasers [18,21–23].
On-orbit geometric calibration of satellite laser altimeters using infrared detectors and corner-cube retroreflectors
Published in International Journal of Digital Earth, 2023
Junfeng Xie, Ren Liu, Xiaomeng Yang, Fan Mo, Fangxu Zhang, Lirong Liu
The infrared laser detector for the GF-7 satellite employs a positive intrinsic-negative diode that covers the 1064 nm wavelength as its core photoelectric conversion device, supplemented by narrowband filters to detect the GF-7 satellite narrow laser pulses. According to laboratory tests, the infrared detector has a dynamic detection range of over 30 times from 3.46 nJ/cm2 to 110.4 nJ/cm2, and the equivalent surface reflectance ranges between 0.03 and 0.6. To ensure that the sensitivity change of the satellite laser within the ±5° incident angle range is less than 5%, a converging lens is installed at the front end of the photodiode inside the infrared detector. In addition, the infrared detector uses narrowband filters to prevent background scattered light in the air above the infrared detector from entering the photosensitive area of the photodiode. By reducing circuit noise through circuit noise reduction methods, the false trigger rate of the entire laser infrared detector is lowered, ultimately ensuring that the false trigger rate of the infrared detector is less than 0.1%. During the production of the infrared detector, electronic components with consistent performance, such as voltage regulators, divider resistors, and comparators, were chosen, and high-precision voltage and amplification circuits were used to compensate for the energy uniformity differences between infrared laser detectors, guaranteeing that the energy consistency difference for each GF-7 satellite infrared laser detector does not exceed 3%. A physical photo of the developed GF-7 satellite infrared laser detector is shown in Figure 3(c), while its internal structure is displayed in Figure 3(d).