The requirement for cooling below room temperature to limit thermal generation processes is the major drawback of infrared (IR) photon detectors. In order to obtain background limited performance (BLIP), the devices for the 3–5 μm spectral region are typically operating at T <200 K, while those for the 8–12 μm at 77 K. The current effort to produce near room temperature photon detectors (higher operating temperature conditions, HOT) are being concentrated on the interband cascade photodetectors (ICIP). That effort is mostly seen for longwave infrared (LWIR) devices operating at HOT conditions where the optimum absorber may be thicker compared to the carriers’ diffusion length, limiting the photogenerated carriers collection what leads to the decreasing of the quantum efficiency (QE) and the ultimate performance cannot be achieved in practice. The ICIP architecture allows to circumvent that issue. In addition to avoid the limitation imposed by the reduced diffusion length, the intersubband (IS) quantum cascade photodetectors (QCPs) were introduced in the early 2000s based on quantum-well infrared photodetectors (QWIPs) and quantum cascade lasers (QCLs). Those cascade detectors proved to be operating at low temperatures ~ 100 K. In this paper we present the current status of the ICIPs based on type-II superlattices (T2SLs) InAs/InAsSb n- and p-type doped active layers intended to be operating within LWIR range and HOT conditions - 210 K reached by thermoelectric coolers and room temperature. Immersed detector reached detectivity, D*~3×108 cmHz1/2/W at 300 K and wavelength, λ=10 μm.
Purpose:The aim of the article is to determine the quality of aged fuels.It has been shown that laboratory tests of resins formed in fuels are insufficient to determine the quality of gasoline.Design/methodology/approach: Morphological tests of deposits released in fuels during longterm storage were carried out.The research was qualitative in nature.Morphological tests of deposits released in fuels during long-term storage were carried out.The research was qualitative in nature.Samples of diesel oil, ON95 and ON98 gasoline were tested.Findings: The novelty of the article is to show that fuels from one manufacturer and stored in the same tank, depending on the fraction, have different properties and significantly differ in quality.In the article different mechanisms of resin release in fuels and their impact on fuel quality were demonstrated.Research limitations/implications: Glass containers were used in the tests, limiting chemical reactions between the tested fuel and the vessel material.On the other hand, aging processes in glass vessels occur slower than in steel tanks.Due to the roughness of the surface, deposits in glass vessels flow off the walls more easily than in steel and PET vessels.Practical implications: It is suggested to thoroughly clean fuel tanks intended for transport or storage and to extend the quality testing of liquid fuels such as gasoline by institutions supervising the quality of fuels on the market.Originality/value: It is to show that fuels from one manufacturer and stored in the same tank, depending on the fraction, have different properties and significantly differ in quality.The article is addressed to institutions dealing with fuel storage.
This article reports the parameters and characteristics of recently introduced mid Infrared (3-12um) detection modules for gas sensing applications. In Mid infrared range one can detect almost every simple or complex compound existing on earth. Currently a driving factors for development of gas sensors are related to air/water quality, explosive material detection and medical applications, especially breath analyzers. Gas sensors require source (thermal, diode or laser), sampling compartment and detection module. At VIGO System we are concentrated on designing and manufacturing high operating temperature detectors, fast, sensitive, affordable and reliable required for development of such platforms. We are using active, absorber elements based on complex HgCdTe or InAsSb heterostructures monolithically integrated with optical immersion lens. Additional collective optics, signal amplification, temperature control and heat dissipation will be also discussed in this article. Those functions are critical for ultimate performance of gas sensors.
