Device Detector Research Articles

Development of a Real-Time Wearable Humming Detector Device.

This study focuses on the development of a wearable real-time Humming Detector Device (HDD) aimed at enhancing the control of assistive devices through humming. As the need for portable user-friendly tools in assistive technology grows, the HDD offers a non-invasive solution to detect vocal cord vibrations. Vibrations, detected thanks to an accelerometer worn on the neck, are processed in real time using a Fast Fourier Transform (FFT) to identify specific humming frequencies, which are then translated into commands for controlling assistive devices via Bluetooth Low Energy (BLE) transmission. The device was tested with 13 healthy subjects to validate its potential and determine the optimal number of distinct commands that users can achieve. The HDD's portability and precision make it a promising alternative to traditional voice recognition systems, particularly for individuals with speech impairments.

Design and fabrication of a dual laser Raman spectrometer with a single one-dimensional CCD detector

The combination of two spectrometers in dual-laser Raman devices without the need for moving parts represents a significant advancement. This study focuses on design and fabrication of a dual spectrometer with no moving components, allowing data to be gathered using a single detector. This instrument consists of two Czerny–Turner optical arrangements which is symmetrically merged. Dual spectrometer single detector has two light inputs, each of them, concentrating the light separately on a one linear charge-coupled device detector through two independent optical paths. In this innovative spectrometer design, no optical moving parts are used, and therefore, the wavelength displacement error in repeating the spectroscopic experiment is zero. The independent nature of the optical paths enables the optimization of each spectrometer arrangement without affecting the other. The final spectrometer has a spectral resolution of 4.6 and 6.11 cm− 1 for Full Width at Half Maximum across the wavelength ranges of 532 to 708 nm and 784.65 to 1100 nm, respectively. Switching between the two different acquisition setups can be done seamlessly and quickly, with the ability to record approximately 2000 spectra per second. Standard neon and mercury-argon lamps’ atomic radiation spectra, along with Raman scattering data from a cyclohexane standard sample, were successfully recorded using laser wavelengths of 532 nm and 784.65 nm.

Application of a Multi-Gas Detector for Monitoring Gas Composition in Minced Beef During Storage.

This study aims to assess the capability of using a specially designed device to monitor changes in gas concentration (CO2, NH3, H2S, and O2) in the atmosphere above the minced beef meat, during storage at refrigerated temperature. With its array of sensing channels, the multi-gas detector device facilitates the detection of precise gas concentrations in sensitive environments, enabling the monitoring of various processes occurring within stored meat. To delve into the connection between microbial activity and gas emissions during storage, fluctuations in microbial populations in the meat were observed, focusing on prevalent meat microbiota such as lactic acid bacteria (LAB) and Enterobacteriaceae. A significant reduction of O2 content in the stored samples was observed after seven days (p < 0.05), while a significant release of CO2 was detected on the fourth day of storage. Significant changes (p < 0.05) in the gas content were tracked until the 11th day of storage followed by intensive microbial growth. NH3 and H2S levels remained undetectable throughout the experiment. The results showed a correlation between an increase in gas content in the headspace and an increase in the number of LAB and Enterobacteriaceae in meat. Modern multi-gas detector devices can indirectly determine microbial contamination in closed meat packaging.

Room temperature mid-wave infrared guided mode resonance InAsSb photodetectors

We demonstrate room temperature operation of mid-wave infrared photodetectors leveraging a guided mode resonance architecture and bulk alloy InAsSb absorbers. Room temperature operation with low dark current is achieved by using detector structures with ultra-thin (150, 250 nm) absorbers leveraging the strong confinement enabled by the guided mode architecture. Devices with 1D and 2D grating arrays are fabricated and characterized, and compared to unpatterned detector devices. We see enhancement in the detectors’ optical response associated with coupling to both TE- and TM-polarized guided modes and good agreement between experimental and theoretically-predicted behavior. We show strong enhancement for unpolarized light incident on 2D grating arrays, with a broader spectral response than observed for polarized light incident upon 1D grating GMR detectors. The bulk InAsSb detectors presented in this work offer enhanced performance at room temperature for a range of imaging and sensing applications.

Ultra-high PDCR(>109) of vacuum-UV photodetector based on Al-doped Ga2O3 microbelts

Al-doped Ga2O3microbelts with widths ranging from 20 to 154μm and lengths up to 2 mm were grown using carbothermal reduction. Based on these ultra-wide microbelts, single-microbelt (37μm wide) and double-microbelts(38μm/42μm wide) metal-semiconductor-metal photoconductive ultraviolet (UV) detectors PDs were fabricated and their optoelectronic performances were investigated at Vacuum-UV (VUV) wavelengths of 185 nm. Under irradiation of 185 nm, the Al-doped Ga2O3PD has a very-high photocurrent (Iph) of 192.07μA and extremely low dark current (Id) of 156 fA at 10 V, and presents a ultra-high light-to-dark current ratio of 1.23 × 109. The responsivity (R), external quantum efficiency (EQE), and detectivity (D*) of the double-microbelts detector device were 1920 A W-1, 9.36 × 105%, and 8.6 × 1016Jones, respectively. Since the bandgap of the Al-doped microbelts becomes wider, and the fabricated detector has weaker sensitivity to radiation in the 254/365 nm wavelengths. Compared with the 254 nm and 365 nm UV cases, the devices under 185 nm VUV show the excellent high selectivity ratios of 1.47 × 106and 1.7× 107, respectively. This paper should provide a new insight on the VUV photodetectors utilizing Ga2O3microbelts.

Development and implementation of a low-cost metal detector device

Development and implementation of a low-cost metal detector device

Measurement of Radon Gas Concentration in Sources of Drinking Water in Makurdi, Benue State, Nigeria Using Radon Detector (RAD-7)

Study’s Excerpt Radon gas contamination across diverse drinking water sources within Makurdi, Nigeria, was investigated. The RAD-7 detector was used, and the results revealed elevated radon levels exceeding WHO limits in some specific locations. There is a need for targeted risk mitigation strategies and continuous monitoring of Radon gas contamination in the area. Full Abstract Concern over radon gas's potential health risks when used or ingested in homes is growing, as is the issue with its presence in sources of drinking water. In this study, water samples were collected from various locations in Makurdi, Benue State, Nigeria, and the amount of radon gas present was measured using the Radon Detector (RAD-7). The study used a methodical sampling strategy to gather water samples from wells, boreholes, and surface water bodies throughout various Makurdi locations. The gathered water samples were examined using the RAD-7 detector, a trustworthy and sensitive device for measuring radon gas. The radon levels ranged from trace levels (20.0 ) to higher quantities (122.0 ), raising worries about potential health implications for nearby people reliant on these water sources. Thirty (30) samples of water were gathered for this investigation. The samples' radon content ranged from 10.3 to 122.0 Bq L-1, which is within the World Health Organization's (WHO) allowable limit and other regulatory bodies (100 Bq L-1) except in the sample collected from Court 5 and Logo1, which was higher than the set limit. The results of the analysis demonstrated that there were large variations within the range of 0.61 0.39-11.80 1.85 and a mean of 57.36 in the amounts of radon gas in the water samples obtained from the different sources. More research and monitoring are advised to gain a complete understanding of radon distribution and to develop workable radon risk reduction plans for water sources.

Mobility Gaps of Hydrogenated Amorphous Silicon Related to Hydrogen Concentration and Its Influence on Electrical Performance.

This paper presents a comprehensive study of hydrogenated amorphous silicon (a-Si)-based detectors, utilizing electrical characterization, Raman spectroscopy, photoemission, and inverse photoemission techniques. The unique properties of a-Si have sparked interest in its application for radiation detection in both physics and medicine. Although amorphous silicon (a-Si) is inherently a highly defective material, hydrogenation significantly reduces defect density, enabling its use in radiation detector devices. Spectroscopic measurements provide insights into the intricate relationship between the structure and electronic properties of a-Si, enhancing our understanding of how specific configurations, such as the choice of substrate, can markedly influence detector performance. In this study, we compare the performance of a-Si detectors deposited on two different substrates: crystalline silicon (c-Si) and flexible Kapton. Our findings suggest that detectors deposited on Kapton exhibit reduced sensitivity, despite having comparable noise and leakage current levels to those on crystalline silicon. We hypothesize that this discrepancy may be attributed to the substrate material, differences in film morphology, and/or the alignment of energy levels. Further measurements are planned to substantiate these hypotheses.

Rapid Detection of Soil Available Phosphorus using Capacitively Coupled Contactless Conductivity Detection

Background: In China, the traditional method for analyzing soil available phospho-rus is inadequate for large-scale soil assessment and nationwide soil formulation demands. To address this, we propose a rapid and reliable method for soil-available phosphorus detection. The setup includes an on-site rapid pre-treatment device, a non-contact conductivity detection device, and a capillary electrophoresis buffer solution system composed of glacial acetic acid and hydroxypropyl-β-cyclodextrin. Methods: The on-site rapid pre-treatment process includes fresh soil moisture content detec-tion (moisture rapid detector), weighing (handheld weighing meter), stirring (handheld rapid stirrer), and filtration (soil rapid filter) to obtain the liquid sample, and direct injection (capil-lary electrophoresis detector). The phosphate ion detection parameters include capillary size, separation voltage, injection parameters, and electric injection. We used Liaoning brown soil, Henan yellow tidal soil, Heilongjiang black soil, and Anhui tidal soil as standard samples. Additionally, we used mathematical modeling methods and machine learning algorithms to analyze and process research data. Results and Conclusion: Following calibration with standard samples, the experimental blind test samples demonstrated conformity with the national standard method, exhibiting a relative standard deviation of less than 3%. The proposed pre-treatment device and non-contact con-ductivity detector are powered by lithium-ion batteries, rendering them ideal for extended field operations. The non-contact conductivity detector obviates the need for direct contact with test samples, mitigating environmental pollution. Furthermore, the neural network model exhibited the highest level of goodness of fit in chemical data analysis.

3D Printing-Induced Hierarchically Aligned Nanocomposites With Exceptional Multidirectional Strain Sensing Performance.

High-performance sensors capable of detecting multidirectional strains are indispensable to understand the complex motions involved in flexible electronics. Conventional isotropic strain sensors can only measure uniaxial deformations or single stimuli, hindering their practical application fields. The answer to such challenge resides in the construction of engineered anisotropic sensing structures. Herein, a hierarchically aligned carbon nanofiber (CNF)/polydimethylsiloxane nanocomposite strain sensor is developed by one-step 3D printing. The precisely controlled printing path and shear flow bring about highly aligned nanocomposite filaments at macroscale and orientated CNF network within each filament at microscale. The periodically orientated nanocomposite filaments along with the inner aligned CNF network successfully control the strain distribution and the appearance of microcracks, giving rise to anisotropic structural response to external deformations. The synergetic effect of the multiscale structural design leads to distinguishable gauge factors of 164 and 0.5 for applied loadings along and transverse to the alignment direction, leading to an exceptional selectivity of 3.77. The real-world applications of the hierarchically aligned sensors in multiaxial movement detector and posture-correction device are further demonstrated. The above findings propose new ideas for manufacturing nanocomposites with engineered anisotropic structure and properties, verifying promising applications in emerging wearable electronics and soft robotics.

Research on angular displacement detection technology of inter-satellite laser communication based on coherent system

With the rapid development of spatial information networks technologies, inter-satellite laser communication links have played an important role in the satellite Internet. High-precision relative angular displacement detection is the foundation for achieving real-time tracking of laser communication links, and its accuracy directly impacts the tracking performance and communication quality of the laser communication link. Traditional laser communication systems utilize intensity-based position detection methods to calculate angular displacement, requiring setting separate Charge Coupled Device (CCD) or Four-quadrant Detector (QD) as well as independent optical tracking branches. This setup makes it difficult to integrate with high-speed coherent communication systems. Additionally, the method employing intensity detection to determine angular displacement based on spot position has lower accuracy in theory. A angular displacement detection of coherent-based inter-satellite laser communication is proposed in this paper. Firstly, real-time calculation of phase differences at different positions of the beam is achieved through heterodyne coherent array detection and dual high-precision phase-locked loops. Then, a model correlating wave front phase difference with relative angular displacement is established, phase noise during beam transmission and detection processes is analyzed, and algorithm for detecting angular displacement in coherent systems is studied. Finally, a laser communication link is constructed under laboratory condition, and experimental validation work is carried out. When the relative angle deviation is 1°, the phase difference changes by 0.089049795 rad, and the angular displacement detection error of 0.66697μrad(σ). When the relative angle error is 0.603873μrad(σ), the detection sensitivity is −43.93dBm. The experimental results show that in the coherent system, the relative angular displacement detection with high precision can be realized by using the wavefront phase difference of beam, which can support the laser communication tracking system to achieve higher precision beam tracking.

Pre-Launch Calibration of the Bidirectional Reflectance Distribution Function (BRDF) of Ultraviolet-Visible Hyperspectral Sensor Diffusers

An Ultraviolet-Visible Hyperspectral Sensors (UVS) instrument is an ultraviolet-visible imaging spectrograph equipped with two-dimensional charge-coupled device detectors. It records both the spectrum and the swath perpendicular to the flight direction, offering a wide 112° swath. This configuration enables global daily ground coverage with high spatial resolution. The absolute values of in-orbit solar irradiance can be evaluated using the bidirectional reflectance distribution function (BRDF), with the measurement accuracy directly affecting the accuracy of constituent inversion. This paper outlines the calibration process for the BRDF of the UVS, detailing the calibration methods and equipment used. It also proposes a BRDF model and discusses key coefficients. The accuracy levels of the UVS in the UV1, UV2, and VIS channels were 2.162%, 2.162%, and 2.173%, respectively.

Improvement of temperature surveillance of neonates in low-resource settings by a simple low-cost device: a descriptive study

IntroductionNeonatal hypothermia in low-resource settings is prevalent and closely associated with high morbidity and mortality. We examined if an easy-to-read temperature detector device improves health outcomes.MethodsIn a descriptive study, 1009...

Experimental Study on Damage Effect of Mid-Infrared Pulsed Laser on Charge Coupled Device (CCD) and HgCgTe Detectors.

As the weak link in electro-optical imaging systems, photodetectors have always faced the threat of laser damage. In this paper, we experimentally investigated the damage mechanism of the photodetector induced by the out-of-band laser. The damage thresholds of the mid-infrared pulsed laser for Charge Coupled Device (CCD) and HgCdTe detectors were determined through damage experiments. The analysis of the damage phenomena and data for both CCD and HgCdTe detectors clearly demonstrated that out-of-band mid-infrared pulsed lasers could entirely incapacitate CCD and HgCdTe detectors. Our analysis of the damage process and data revealed that the primary mechanism of damage to CCD and HgCdTe detectors by mid-infrared pulsed lasers was primarily thermal. This study serves as a reference for further research on the mid-infrared pulsed laser damage mechanisms of CCD and HgCdTe detectors, as well as for laser protection and performance optimization in imaging systems.

Characterisation of Sn-Cl co-doped β-Ga2O3 thin films deposited via spray pyrolysis and their application in UV detector devices

Ga2O3, an ultrawide bandgap semiconducting oxide, is currently emerging as a promising candidate for various applications, such as power devices, solar-blind UV detectors, high temperature oxygen sensors and biomedical imaging. One significant limitation hindering the application of Ga2O3 as a wide-bandgap semiconductor is its poor conductivity. In this work, we investigate whether doping with tin and chlorine can mitigate this condition. Sn-Cl co-doped β-Ga2O3 thin films are deposited on glass substrates using spray pyrolysis technique. The deposited films are subjected to comprehensive analysis, including structural, optical and morphological measurements using techniques like X-ray diffraction, UV-Vis-NIR spectroscopy, X-ray photoelectron spectroscopy and EDX studies. Electrical properties are assessed using the four-probe method and Hall measurements. The best conductivity of 8.86 Ω−1m−1 is observed when 8.68 at% of Sn and 3.37 at% of Cl were co-doped into Ga2O3 (S(3)) and its optical band gap is calculated to be 4.65 eV. This is about five orders of improvement in conductivity as compared to that of pure Ga2O3 thin film deposited by the same method. Furthermore, we have constructed a deep UV detector utilizing doped β-Ga2O3 thin films as the semiconducting absorbing layer. The detector demonstrated the highest responsivity of 2.54 × 10−4 A/W at 260 nm and the corresponding specific detectivity is 1.4 × 109 Jones. The current research validates the potential of Sn-Cl co-doped β-Ga2O3 thin film as an excellent choice for UV detector application.

Composition Dictates Octahedral Tilt and Photostability in Halide Perovskites.

Halide perovskites are excellent candidate materials for use in solar cell, LED, and detector devices, in part because their composition can be tuned to achieve ideal optoelectronic properties. Empirical efficiency optimization has led the field toward compositions rich in FA (formamidinium) on the A-site and I on the X-site, with additional small amounts of MA (methylammonium) or Cs A-site cations and Br X-site anions. However, it is not clear how and why the specific compositions of alloyed, that is, mixed component, halide perovskites relate to photo-stability of the materials. Here, this work combines synchrotron grazing incidence wide-angle X-ray scattering, photoluminescence, high-resolution scanning electron diffraction measurements and theoretical modelling to reveal the links between material structure and photostability. Namely, this work finds that increased octahedral titling leads to improved photo-stability that is correlated with lower densities of performance-harming hexagonal polytype impurities. These results uncover the structural signatures underpinning photo-stability and can therefore be used to make targeted changes to halide perovskites, bettering the commercial prospects of technologies based on these materials.

PbS/ Si NW Heterojunction on Silicon Chip Based Self-Powered Photo Detector Device for IR Radiations by Chemical Bath Deposition

PbS/ Si NW Heterojunction on Silicon Chip Based Self-Powered Photo Detector Device for IR Radiations by Chemical Bath Deposition

Flexural-gravity wave forces acting on a submerged spherical object over a flexible sea bed

ABSTRACT A study has been conducted to analyse the impact of an ice sheet on the flexural-gravity wave force acting on a neutrally buoyant, spherical object immersed in a sea in accordance with the linear wave hypothesis. The bottom of the sea is presumed to be protected by a surface composed of some sort of flexibility, and the top is enclosed by an ice sheet. The solution to a diffraction problem is established using the multipole method. The estimated vertical and horizontal flexural-gravity wave forces are visualized in relation to different immersion depths of the spherical body, depths of the fluid and various flexural rigidities of the ice plate and the flexible seabed. The approach adopted here is likely to be of immense significance in the construction of various spherical gadgets like a seabed pressure detector device for tsunami recognition or communication in crisis for a submarine in earthquake zones.

Recent advancement in the synthesis of zinc sulphide thin films

This research work has given an overview on the preparation of zinc sulphide thin films on different types of substrates (quartz, soda lime glass, silicon, polyethylene terephthalate film, fluorine-doped tin oxide glass, indium tin oxide coated glass, silica, stainless steel, mica, microscopy glass slide and (100) GaAs substrate) using different types of deposition methods. XRD data showed information about the different phases (cubic, wurtzite and hexagonal) presented in the obtained as-deposited films and annealed samples. Based on optical studies, the band gap was observed in the range of 2.6 eV to 3.87 eV with good absorption coefficient value (105 to 106 cm-1). Experimental results indicated these films could be used in solar cell applications, anti-reflection coating, photocatalysts, photo detector devices and laser-oriented coating applications.

Ultra-sensitive current bistability and light switching in a resonant tunneling superlattice transistor

Bistability in the current–voltage characteristics of semiconductor superlattices and quantum cascade laser structures has the potential for wide-ranging applications, particularly in sensing systems. However, the interdependency of applied bias and current injection in conventional two-terminal structures has led to complications in analysis and rendered the bistability phenomenon difficult to implement in practical applications. Here, we report a new kind of electronic bistability coupled to optical switching in a resonant tunneling bipolar superlattice transistor. This bistability manifests as sharp discontinuities in the collector current with extremely small variations of the applied voltage, which arise from unstable tunneling transmission across the hetero-barrier between the two-dimensional electron gas (2DEG) at the edge of the transistor base and the collector superlattice structure. The electronic transitions between high and low quantum mechanical transmissions are demonstrated to be caused by self-consistent variations of the internal electric field at the heterointerface between the 2DEG and the superlattice. They are also present in the base current of the three-terminal device and result in sharp switching of near-infrared spontaneous light emission output from an interband radiative recombination process with a peak emission wavelength of 1.58 μm. A comprehensive quantum mechanical theoretical model accounting for the self-consistent bistable tunneling transmission is in quantitative agreement with the experimental data. The measured peak transconductance sensitivity value of 6000 mS can be used in the highly sensitive detector and non-linear device applications.