Fabrication Of Detectors Research Articles

Portable urine alcohol detector fabrication with arduino microcontroller-based MQ-3 sensor

An alcohol detector in urine is a tool that can detect alcohol in a person's urine. This tool detects Ethanol gas using the MQ-3 sensor. The MQ-3 sensor is an analog sensor that has a 5 volt DC power supply specification. Arduino Uno as a data processor obtained from reading the MQ-3 sensor and displayed on the LCD. This tool detects alcohol in a person's urine until it is known whether liquor is in the urine or not. From the design of this urine alcohol detector, the test results show an increase in the ADC sensor value when the sensor detects alcohol. It is known that it takes a different time for the sensor to return to the initial value of various alcohol concentrations. This study concluded that the sensor worked well until the alcohol concentration was 0.1%. The sensor also needed time to return to the starting point, directly proportional to the alcohol concentration examined.

SU-8 processing improvement and simulating studies for a Micromegas detector fabrication

This paper reports the manufacturing methodology to produce an electron multiplier, a Micromegas device, integrated onto a micro-pixel readout anode using a Silicon wafer as a holder. It describes the improvement in the processing of the insulating grid material SU-8 and electrical tests with the device. For the latter purpose, simulations with Garfield++ are carried out to predict the detector response for different gas mixtures. The Micromegas detector sandwich proposed in this work presents a series of problems, which we have addressed and discussed within this paper. The temperature control throughout the processing of SU-8 is extremely important, to be able to develop it. When developing the final SU-8 layer, we have used an extra photoresist, which combined with the SU-8, resulted in a much-improved shape of the Micromegas SU-8 hole-grid. Electrical testes are performed in order to verify the signals produced by a 55Fe radioactive source. A gas gain about 1,3 × 102, using Ar/C2H6 (75/25) mixture, is achieved for the prototype manufactured.

Defect characterization and charge transport measurements in high-resolution Ni/n-4H-SiC Schottky barrier radiation detectors fabricated on 250 μm epitaxial layers

Advances in the growth processes of 4H-SiC epitaxial layers have led to the continued expansion of epilayer thickness, allowing for the detection of more penetrative radioactive particles. We report the fabrication and characterization of high-resolution Schottky barrier radiation detectors on 250 μm thick n-type 4H-SiC epitaxial layers, the highest reported thickness to date. Several 8 × 8 mm2 detectors were fabricated from a diced 100 mm diameter 4H-SiC epitaxial wafer grown on a conductive 4H-SiC substrate with a mean micropipe density of 0.11 cm−2. From the Mott–Schottky plots, the effective doping concentration was found to be in the range (0.95–1.85) × 1014 cm−3, implying that full depletion could be achieved at ∼5.7 kV (0.5 MV/cm at the interface). The current-voltage characteristics demonstrated consistently low leakage current densities of 1–3 nA/cm2 at a reverse bias of −800 V. This resulted in the pulse-height spectra generated using a 241Am alpha source (5486 keV) manifesting an energy resolution of less than 0.5% full width at half maximum (FWHM) for all the detectors at −200 V. The charge collection efficiencies (CCEs) were measured to be 98–99% with no discernable correlation to the energy resolution. A drift-diffusion model fit to the variation of CCE as a function of bias voltage, revealed a minority carrier diffusion length of ∼10 μm. Deep level transient spectroscopy measurements on the best resolution detector revealed that the excellent performance was the result of having ultralow concentrations of the order of 1011 cm−3 lifetime limiting defects—Z1/2 and EH6/7.

Effect of 150 MeV protons on carbon nanotubes for fabrication of a radiation detector

High energy and high flux protons are used in proton therapy and the impact of proton radiation is a major reliability concern for electronics and solar cells in low earth orbit as well as in the trapped belts. Carbon nanotubes (CNTs), due to their unique characteristics, have been considered for the construction of proton and other radiation sensors. Here, a single wall CNT based proton sensor was fabricated on FR4 substrate and its response to 150 MeV proton irradiation was studied. The change in the resistance of the nanotubes upon irradiation is exploited as the sensing mechanism and the sensor shows good sensitivity to proton radiation. Proton radiation induces dissociation of ambient oxygen, followed by the adsorption of oxygen species on the nanotube surface, which influences its electrical characteristics. Since the nanotube film is thin and the 150 MeV protons are expected to penetrate into and interact with the substrate, control experiments were conducted to study the impact on FR4 substrate without the nanotubes. The dielectric loss tangent or dissipation factor of FR4 increases after irradiation due to an increase in the cross-linking of the resin arising from the degradation of the polymer network.

Broadband infrared photodetection using a narrow bandgap conjugated polymer.

Photodetection spanning the short-, mid-, and long-wave infrared (SWIR-LWIR) underpins modern science and technology. Devices using state-of-the-art narrow bandgap semiconductors require complex manufacturing, high costs, and cooling requirements that remain prohibitive for many applications. We report high-performance infrared photodetection from a donor-acceptor conjugated polymer with broadband SWIR-LWIR operation. Electronic correlations within the π-conjugated backbone promote a high-spin ground state, narrow bandgap, long-wavelength absorption, and intrinsic electrical conductivity. These previously unobserved attributes enabled the fabrication of a thin-film photoconductive detector from solution, which demonstrates specific detectivities greater than 2.10 × 109 Jones. These room temperature detectivities closely approach those of cooled epitaxial devices. This work provides a fundamentally new platform for broadly applicable, low-cost, ambient temperature infrared optoelectronics.

Influence of Pixel Etching on Electrical and Electro-Optical Performances of a Ga-Free InAs/InAsSb T2SL Barrier Photodetector for Mid-Wave Infrared Imaging

In this paper, the influence of etching depth on the dark current and photo-response of a mid-wave infrared Ga-free T2SL XBn pixel detector is investigated. Two wet chemical etching depths have been considered for the fabrication of a non-passivated individual pixel detector having a cut-off wavelength of 5 µm at 150 K. This study shows the strong influence of the lateral diffusion length of a shallow-etched pixel on the electro-optical properties of the device. The lowest dark current density was recorded for the deep-etched detector, on the order of 1 × 10−5 A/cm2 at 150 K and a bias operation equal to −400 mV. The corresponding quantum efficiency was measured at 60% (without anti-reflection coating) for a 3 µm thick absorbing layer. A comparison of experimental results obtained on the two kinds of etched pixels demonstrates the need for a deep-etching process combined with efficient passivation for FPA manufacturing.

Investigation of grown ZnS film on HgCdTe substrate for passivation of infrared photodetector

Zinc sulfide (ZnS) thin films were developed on the mercury cadmium telluride (HgCdTe) substrate using the thermal evaporation technique and investigated with X-ray diffraction, energy dispersive analysis of X-rays, atomic force microscopy (AFM) and capacitance-voltage (C-V). The obtained results confirm that the films have a cubic zinc-blend structure with (111) preferred orientation and nearly stoichiometric composition. The AFM measurement reveals that the film is uniform, densely packed and has a smooth surface or very low roughness. The C-V measurement of a ZnS/HgCdTe based metal-insulator-semiconductor device provides the utility of ZnS thin film as a passivation layer for the HgCdTe substrate. The evaluated fixed-charge density, slow state density and fast state density of the device are 4.98 × 1010 cm−2, 4.22 × 1010 cm−2 and 5.32 × 1011 cm−2 eV−1, respectively. Thus, the grown ZnS thin film could be used as a suitable passivation agent in HgCdTe-based infrared detector fabrication.

Bismuth tri-iodide-polystyrene composite for X-rays switching applications at room temperature

Bismuth tri-iodide is potential low toxic material for fabrication of room-temperature X-rays detector due to its relatively high atomic number and density. However, on increasing the thickness of detector, higher leakage current at low bias voltage and low mechanical strength are major issues in utilizing its full potential in radiation detection and in other practical applications. BiI3-polystyrene composite pellets was prepared to get unique defects tolerance nature of material that improves signal/noise ratio. BiI3-polystyrene composite was prepared by low-cost dry-tumble mixing technique. XRD observations gives information of preferred orientated planes perpendicular to c-axis and morphology study by SEM also confirms the same orientation. X-rays switching response recorded at different voltages (13–100 V) for detector performance measurements. Resistivity of BiI3 (107ohm-cm) is less as compared to polystyrene (1015ohm-cm), it acts as conductive-tips in polystyrene-matrix and improves charge transfer to electrodes. These superior charge transfer properties lead to high photocurrent on-off ratio to 70 and suppress leakage current.

Effect of Pt-doped on the photocurrent of MSM photodetector

This article report the fabrication and characteristics of MSM photo detector by compare between non-doped and doped platinum (Pt) atom. Fabrication process has same but different in Pt doping process for atom doping and diffusion process. The metal finger width 2um with 50 um spacing between metal contact. At bias voltage 10 voltage show higher capacitance-voltage and photocurrent increase after doped with Pt atom. By experiment shows photocurrent increase around 4 times from 45.98 to 197.22 uA at bias 10 voltage by photoluminescence 25,000 lux.

A high-response ultraviolet photodetector by integrating GaN nanoparticles with graphene

Abstract A new type of ultraviolet photodetector was fabricated by integrating GaN nanoparticles as the absorber and graphene as the carrier transport channel. The GaN nanoparticles prepared by metal-organic chemical vapor deposition exhibited the average diameter, height and density of 87.2 nm, 18.4 nm and 5 × 109/cm2, respectively. The chemical component and optical properties of the GaN nanoparticles were also confirmed and discussed. The monolayer graphene film was transferred onto GaN nanoparticles for the detector fabrication, which possessed the high crystalline quality and uniform coverage. Since the GaN nanoparticles providing trap states for the photo-generated hole, a longer carrier lifetime and higher gain would be obtained. In addition, based on the high carrier mobility of the graphene, the ultraviolet photodetector exhibited a persistent photoconduction effect and achieved a high responsivity of 200.69 A/W. The Kelvin probe force microscope measurements were carried out to reveal the device work mechanism and the carrier transport model has been established according to the decreased graphene surface potential of 0.2 eV before and after contacting with the GaN nanoparticles. Present work provides a method for obtaining new types of Ⅲ-nitrides-based ultraviolet photodetectors with high response.

Dislocation density reduction using overgrowth on hole arrays made in heteroepitaxial diamond substrates

The growth of large-area diamond films with low dislocation density is a landmark in the fabrication of diamond-based power electronic devices or high-energy particle detectors. Here, we report the development of a growth strategy based on the use of micrometric laser-pierced hole arrays to reduce dislocation densities in heteroepitaxial chemical vapor deposition diamond. We show that, under optimal growth conditions, this strategy leads to a reduction in dislocation density by two orders of magnitude to reach an average value of 6 × 105 cm−2 in the region where lateral growth occurred, which is equivalent to that typically measured for commercial type Ib single crystal diamonds.

Single-photon avalanche diode detectors based on group IV materials

Today there are several types of photodetectors that can cope with the task of detecting a single photon, however, avalanche photodiodes are most widely used for applications in fiber-optic communication systems and quantum cryptography. In the past 5 years experimental fabrication of single-photon avalanche detectors within conventional complementary metal–oxide–semiconductor technology and by the method of molecular beam epitaxy have made possible many demonstrations of avalanche photodetectors with exceptional performance characteristics and opened wide perspectives for development of devices of new generation. In this work, we review state-of-the-art designs of single-photon avalanche photodiodes based on group IV materials, their operating characteristics, and achieved values of basic parameters, as well as the methods of their synthesis, and outline the perspectives of using such structures in emerging device applications.

Organic polymer and perovskite CdSe–CdS QDs hybrid thin film: a new model for the direct detection of light elements

A window-less X-ray detector fabrication is a challenging job for physicists and technologists. Using a high atomic number (Z) nano-particles (NPs), such as CdSe–CdS quantum dots (QDs) in nano-form, are the most versatile nano-particles and the most suitable choice for energy-dispersive X-ray spectroscopy analysis of light elements. There is no report on the fabrication of a windowless X-ray detector by using core–shell CdSe–CdS QDs, so far as we know. We have observed the luminescence properties of CdSe/CdS core–shell QDs–cellulose hybrid thin films and characterized them. The blaze union of high photoluminescence (PL) of CdSe/CdS core–shell QDs was synthesized by a high-temperature short-time handling approach with a quantum yield of 70%. The surface, configurationally characterizations, and optical characteristics of the above thin films were examined utilizing X-ray diffraction, transmission electron microscopy, PL, scanning electron microscopy, and I–V trademark strategies. This experimental work confirmed thin films coated with QDs of core–shell CdSe–CdS which improve the PL capability of nano-crystalline cellulose. The distribution of a quantum size possesses a rigid structure in the total growth process of the entire shell during the experiment, which is indicated in the absorption spectra followed by a sharp PL peak at 630 nm. It is expected that the present study will have a good promise for X-ray-sensing applications.

Advantages and limitation of Mn doped PIN–PMN–PT single crystals in pyroelectric detectors

The outstanding pyroelectric coefficient p of Mn:PIN–PMN–PT makes it an interesting material for application in pyroelectric infrared detectors. In comparison to the standard material lithium tantalate (LT), the pyroelectric coefficient is higher by a factor of 4. On the other hand, the dielectric permittivity εp is about one order of magnitude higher compared to LT. Due to the higher permittivity, the resulting Figures of Merit (FOM) show the highest performance advantages for Mn:PIN–PMN–PT in the lower frequency range between 1 Hz and 10 Hz. The FOM FR of 278 · 10−12 m/V exceeds by half an order of magnitude the value of LT of 54 · 10−12 m/V. Outstanding specific detectivities around D* ≈ 1.0 · 109 cm√Hz/W at low frequencies even at a relatively low chip size were achieved. The detector fabrication needs adaption of the processes to avoid depolarization due to high temperature impact or mechanical stress.

Ultraviolet photodetector based on NaTaO3/ZnO composite with enhanced photoelectric performance

NaTaO3/ZnO composites were synthesized via a two-step hydrothermal method. Then ultraviolet detectors based on pure NaTaO3, ZnO and their composites with different mole ratio were fabricated. Among all the devices, the 1:1 NaTaO3/ZnO possessed a high photo-to-dark current ratio and stable periodic photoresponse. The photoresponse is facilitated by the synergistic effect between different components and the improved ZnO morphology in the composites, the reduced dimensionality in which provides a straight electron conduction pathway. Additionally, the 1:1 NaTaO3/ZnO detector also exhibits a low dark current less than 1 nA at 5 V bias, which benefits a lot to the low power dissipation and high sensitivity of devices. These results reveal that NaTaO3/ZnO composites are good candidates for the fabrication of ultraviolet detectors.

Fabrication, characterization and analysis of a prototype high purity germanium detector for ^{76}Ge-based neutrinoless double beta decay experiments

Experiments searching for the neutrinoless double beta decay in ^{76}Ge are currently achieving the lowest background level and, in connection with the excellent energy resolution of germanium detectors, they exhibit the best discovery potential for the decay. Expansion to a ton scale of the active target mass is presently considered – in this case on-site production of the detectors may be an option. In this paper we describe the fabrication and characterization procedures of a prototype detector with a small p+ contact, which enhances the abilities of the pulse shape discrimination – one of the most important tools for background reduction. Simulations of the shapes of pulses from the detector were carried out and tuned, taking the advantage of the fact that all the parameters of the Ge crystal, cryostat and of the spectroscopic chain were known. As a result, the pulse shape analyses performed on the simulated and measured data agree very well. The worked out method allows to optimize geometry and crystal parameters in terms of pulse shape analysis efficiency, before the actual production of the detectors.

Characterization of CdZnTeSe Nuclear Detector Chemically Etched in Bromine Methanol

Semiconductor nuclear radiation detectors made from tertiary and quaternary compounds of cadmium telluride (CdTe) can operate at room temperature without cryogenic cooling. One of such materials that have become of great interest is cadmium zinc telluride selenide (CdZnTeSe). Compared to other CdTe-based materials, such as cadmium zinc telluride (CdZnTe), CdZnTeSe can be grown with much less Te inclusions and sub-grain boundary networks. Chemical etching is often used to smoothen wafer surfaces during detector fabrication. This paper presents the characterization of CdZnTeSe that is chemically etched using bromine methanol solution. Infrared imaging shows that the wafer has no sub-grain boundary networks that often limit detector performance. The current-voltage (I-V) characterization experiment gave a resistivity of 4.6 × 1010 Ω-cm for the sample. The I-V curve was linear in the ±10 to ±50 volts range. An energy resolution of 7.2% was recorded at 100 V for the 59.6-keV gamma line of 241Am.

Fabrication and Characteristics of MgZnO Ultraviolet Detector Based on Ag Microporous Array Structure Electrode

Fabrication and Characteristics of MgZnO Ultraviolet Detector Based on Ag Microporous Array Structure Electrode

Fabrication and Characterization of Gaseous Detector for the identification of High Energy Particles.

There is a vast range of gases which get ionized, produce electron-ion pairs, on the passage of high energy charged particles. Such gases are extensively used in experiments such as LHC, Belle-II, RHIC, DAFNE, etc which produce high energy particles. Panjab University established a detector assembly and characterization laboratory dedicated to gaseous detectors such as Resistive Plate Chamber (RPC) and Gas Electron Multiplier (GEM) for the LHC experiment. Here, we present the recent work on the fabrication and characterizations of the GEM detector at Panjab University.

Manufacturability and Stress Issues in 3D Silicon Detector Technology at IMB-CNM.

This paper provides an overview of 3D detectors fabrication technology developed in the clean room of the Microelectronics Institute of Barcelona (IMB-CNM). Emphasis is put on manufacturability, especially on stress and bow issues. Some of the technological solutions proposed at IMB-CNM to improve manufacturability are presented. Results and solutions from other research institutes are also mentioned. Analogy with through-silicon-via technology is drawn. This article aims at giving hints of the technology improvements implemented to upgrade from a R&D process to a mature technology.