Pd/AlN/Si or SiC Structure for Hydrogen Sensing Device

2000 ◽  
Vol 622 ◽  
Author(s):  
Flaminia Serina ◽  
C. Huang ◽  
G. W. Auner ◽  
R. Naik ◽  
S. Ng ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Hydrogen Sensor ◽  
Plasma Source ◽  
Metal Electrode ◽  
Pressure Effects ◽  
Mis Structure ◽  
Hydrocarbon Gases ◽  
Hydrogen Sensing ◽  
Design Structure ◽  
Aln Film

ABSTRACTAn AlN (insulator) MIS Hydrogen Sensor was created using plasma source molecular beam epitaxy (PSMBE) deposition on Si (111) and 6H-SiC. A Pd layer was deposited on top of the AlN film via magnetron sputtering technique utilizing a hard mask. Pd was chosen since H2 readily diffuses within its bulk, thus Pd acts not only as a metal electrode of the MIS structure, but also as a catalyst for hydrogen dissociation. To optimize the design structure several sensors with different AlN and Pd thickness have been developed. RHEED and XRD measurements show that AlN film is epitaxial on both Si (111) and 6H-SiC substrates. The sensors were characterized using capacitance versus voltage C(V) and I(V) measurements, at different frequencies ranging from 1kHz to 1 MHz. Shifts in the C-V and I-V curves occurred with the introduction of hydrogen in the chamber. The temperature, hydrogen partial pressure, effects of oxygen and hydrocarbon gases, insulator and metal thicknesses on sensor response were analyzed.

Palladium and Aluminum Gate Metals/Aluminum Nitride/Silicon Balanced Capacitors for Selective Hydrogen Sensing

2001 ◽  
Vol 693 ◽  
Author(s):  
H. E. Prakasam ◽  
F. Serina ◽  
C. Huang ◽  
G. W. Auner ◽  
L. Rimai ◽  
...  
Keyword(s):  
Practical Importance ◽  
Plasma Source ◽  
Hydrocarbon Gases ◽  
Metal Insulator ◽  
Hydrogen Sensing ◽  
Material Sources ◽  
Sensor Structure ◽  
Electrical Component ◽  
Clear Shift ◽  
Mis Devices

AbstractAn alternate array of Pd/AlN/Si and Al/AlN/Si metal-insulator-semiconductor (MIS) devices has been developed using plasma source molecular beam epitaxy (PSMBE) method for deposition of AlN on Si and magnetron sputtering for deposition of Pd and Al electrodes (via mask) on AlN. Both devices show essentially identical capacitance (C) versus voltage (V) characteristics of the typical MIS capacitor. However, the C-V characteristic of a Pd-device shows a clear shift in the presence hydrogen, while that of an Al-device shows no shift. These sensors were characterized using C(V) and C(time) measurements under varying hydrogen concentration. The effects of oxygen and hydrocarbon gases on the sensors were also studied. The Pd-device responds selectively to hydrogen. These results suggest the possibility of fabricating a balanced sensor structure, which might have significant practical importance, as it would cancel all thermal and material sources of drift in the electrical component of the sensor response.

A Study of Pt/AlN/6H-SiC MIS Structures for Device Applications

2000 ◽  
Vol 622 ◽  
Author(s):  
Margarita P. Thompson ◽  
Gregory W. Auner ◽  
Changhe Huang ◽  
James N. Hilfiker
Keyword(s):  
Plasma Source ◽  
Film Structure ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Current Voltage ◽  
Aln Film ◽  
Capacitance Voltage ◽  
Device Applications ◽  
Current Densities ◽  
Mis Structures

ABSTRACTAlN films with thicknesses from 53 to 79 nm were deposited on 6H-SiC substrates via Plasma Source Molecular Beam Epitaxy (PSMBE). The influence of deposition temperature on the growth mode and film roughness was assessed. The optical constants of the films in the range 0.73-8.75 eV were determined using spectroscopic ellipsometry. Pt/AlN/6H-SiC MIS structures were created and current-voltage (I-V) and capacitance-voltage (C-V) measurements were performed at room temperature and at 250°C. Most of the MIS structures showed rectifying I-V characteristics regardless of growth temperature. A 120-nm-thick AlN film was deposited at 500°C. MIS structures created on this film showed a very low leakage current densities of 6×10−8 A/cm2. The dielectric constant of the film was estimated at approximately 9. The relation between film structure and electrical properties of the films is discussed.

Nitrogen doping of molecular beam epitaxially grown CdTe with a radio-frequency plasma source

1994 ◽  
Vol 138 (1-4) ◽  
pp. 443-447 ◽  
Author(s):  
K.A. Dhese ◽  
D.E. Ashenford ◽  
J.E. Nicholls ◽  
P. Devine ◽  
B. Lunn ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Nitrogen Doping ◽  
Molecular Beam ◽  
Plasma Source ◽  
Radio Frequency Plasma ◽  
Frequency Plasma

A noble gas sensor platform: linear dense assemblies of single-walled carbon nanotubes (LACNTs) in a multi-layered ceramic/metal electrode system (MLES)

2018 ◽  
Vol 6 (5) ◽  
pp. 972-979 ◽  
Author(s):  
Tae-Yeon Hwang ◽  
Yomin Choi ◽  
YoSeb Song ◽  
Nu Si A. Eom ◽  
Seil Kim ◽  
...  
Keyword(s):  
Noble Gas ◽  
Cost Effective ◽  
Hydrogen Sensor ◽  
Metal Electrode ◽  
Electrode System ◽  
Sensor Platform ◽  
Walled Carbon Nanotubes ◽  
Effective Hydrogen ◽  
Layered Ceramic ◽  
Pt Catalyzed

Monodispersed nano Pt catalyzed linear dense assembly of SWCNTs bundles on a noble multi-layered electrode system for cost-effective hydrogen sensor.

scholarly journals Fiber Optical Hydrogen Sensor Based on WO3-Pd2Pt-Pt Nanocomposite Films

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 128
Author(s):  
Jixiang Dai ◽  
Yi Li ◽  
Hongbo Ruan ◽  
Zhuang Ye ◽  
Nianyao Chai ◽  
...  
Keyword(s):  
Optical Power ◽  
Single Mode ◽  
Hydrogen Sensor ◽  
Single Mode Fiber ◽  
Nanocomposite Films ◽  
Electric Signal ◽  
Hydrogen Sensing ◽  
Air Atmosphere ◽  
Sensing Material ◽  
Wide Range

In this paper, WO3-Pd2Pt-Pt nanocomposite films were deposited on a single mode fiber as the hydrogen sensing material, which changes its reflectivity under different hydrogen concentration. The reflectivity variation was probed and converted to an electric signal by a pair of balanced InGaAs photoelectric detectors. In addition, the performance of the WO3-Pd2Pt-Pt composite film was investigated under different optical powers, and the irrigating power was optimized at 5 mW. With the irrigation of this optical power, the hydrogen sensitive film exhibits quick response toward 100 ppm hydrogen in air atmosphere at a room temperature of 25 °C. The experimental results demonstrate a high resolution at 5 parts per million (ppm) within a wide range from 100 to 5000 ppm in air. This simple and compact sensing system can detect hydrogen concentrations far below the explosion limit and provide early alert for hydrogen leakage, showing great potential in hydrogen-related applications.

scholarly journals Investigations of Different Ion Intercalations on the Performance of FBG Hydrogen Sensors Based on Pt/MoO3

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4775 ◽  
Author(s):  
Gaopeng Wang ◽  
Shiwen Yang ◽  
Jixiang Dai ◽  
Yutang Dai ◽  
Tong Zou ◽  
...  
Keyword(s):  
Layer Structure ◽  
Hydrogen Sensor ◽  
Hydrogen Sensors ◽  
Practical Application ◽  
Crystalline Layer ◽  
Optimal Amount ◽  
Hydrogen Sensing ◽  
Sensing Material ◽  
Ionic Bonds ◽  
Ion Species

α-MoO3 has been used as a hydrogen sensing material due to its excellent properties and unique crystalline layer structure. However, the low repeatability of α-MoO3 based hydrogen sensor restricts its practical application. In this paper, the effect of intercalated ion species and the amount in α-MoO3 is experimentally investigated and discussed. It is concluded that the repeatability of the sensor depends on the radius of intercalated ions and amount of ionic bonds. The optimal ion species is Na+ and the optimal amount of precursor is 1 mmol.

p‐type CdSe grown by molecular beam epitaxy using a nitrogen plasma source

1994 ◽  
Vol 65 (4) ◽  
pp. 466-468 ◽  
Author(s):  
Takeo Ohtsuka ◽  
Junji Kawamata ◽  
Ziqiang Zhu ◽  
Takafumi Yao
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Plasma Source ◽  
Nitrogen Plasma ◽  
P Type

scholarly journals Hydrogen Sensor Of TiO2-Based Nanomaterials

2015 ◽  
Vol 60 (2) ◽  
pp. 935-940 ◽  
Author(s):  
B. Łysoń-Sypień ◽  
K. Zakrzewska ◽  
M. Gajewska ◽  
M. Radecka
Keyword(s):  
Gas Sensing ◽  
Hydrogen Sensor ◽  
Integrating Sphere ◽  
Flame Spray ◽  
X Ray Diffraction ◽  
Hydrogen Sensing ◽  
Transmission Electron ◽  
Optical Spectrometry ◽  
Flame Spray Synthesis ◽  
Reference Atmosphere

Abstract The aim of this research was to examine gas sensing properties of TiO2 based nanomaterials. Nanopowders of Cr doped TiO2 with constant Specific Surface Area, SSA, were obtained using Flame Spray Synthesis technique, FSS. Nanomaterials were characterized by Brunauer – Emmett – Teller adsorption isotherms, BET, X – ray diffraction, XRD, Transmission Electron Microscopy, TEM, optical spectrometry UV – vis with the use of an integrating sphere as well as impedance spectroscopy. Detection of hydrogen was carried out over the concentration range of 50 - 3000 ppm at the temperatures extending from 200 to 400°C and synthetic air working as a reference atmosphere. As a result of experiments it appeared that incorporation of 5 at.% of Cr into TiO2 improved hydrogen sensing features due to small crystallite size and predominance of rutile polymorphic phase.

scholarly journals The Role of ALD-ZnO Seed Layers in the Growth of ZnO Nanorods for Hydrogen Sensing

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 491 ◽  
Author(s):  
Yangming Lu ◽  
Chiafen Hsieh ◽  
Guanci Su
Keyword(s):  
Zinc Oxide ◽  
Surface Area ◽  
Gas Sensing ◽  
Zno Nanorods ◽  
Clean Energy ◽  
Hydrogen Sensor ◽  
Zno Films ◽  
Hydrogen Sensing ◽  
Highly Sensitive ◽  
Seed Layers

Hydrogen is one of the most important clean energy sources of the future. Because of its flammability, explosiveness, and flammability, it is important to develop a highly sensitive hydrogen sensor. Among many gas sensing materials, zinc oxide has excellent sensing properties and is therefore attracting attention. Effectively reducing the resistance of sensing materials and increasing the surface area of materials is an important issue to increase the sensitivity of gas sensing. Zinc oxide seed layers were prepared by atomic layer deposition (ALD) to facilitate the subsequent hydrothermal growth of ZnO nanorods. The nanorods are used as highly sensitive materials for sensing hydrogen due to their inherent properties as oxide semiconductors and their very high surface areas. The low resistance value of ALD-ZnO helps to transport electrons when sensing hydrogen gas and improves the sensitivity of hydrogen sensors. The large surface area of ZnO nanorods also provides lots of sites of gas adsorption which also increases the sensitivity of the hydrogen sensor. Our experimental results show that perfect crystallinity helped to reduce the electrical resistance of ALD-ZnO films. High areal nucleation density and sufficient inter-rod space were determining factors for efficient hydrogen sensing. The sensitivity increased with increasing hydrogen temperature, from 1.03 at 225 °C, to 1.32 at 380 °C after sensing 100 s in 10,000 ppm of hydrogen. We discuss in detail the properties of electrical conductivity, point defects, and crystal quality of ALD-ZnO films and their probable effects on the sensitivity of hydrogen sensing.

Wearable colorimetric sensing fiber based on polyacrylonitrile with PdO@ZnO hybrids for the application of detecting H2 leakage

2020 ◽  
Vol 90 (19-20) ◽  
pp. 2198-2211
Author(s):  
Sung-Ho Hwang ◽  
Young Kwang Kim ◽  
Soon Moon Jeong ◽  
Changsoon Choi ◽  
Ka Young Son ◽  
...  
Keyword(s):  
Color Change ◽  
Hydrogen Sensor ◽  
Hydrogen Gas ◽  
Hybrid Nanoparticles ◽  
Hydrogen Sensors ◽  
Colorimetric Sensing ◽  
Hydrogen Sensing ◽  
Detection Systems ◽  
Sensing Material ◽  
Novel Method

A colorimetric hydrogen sensor has great potential for accurately detecting and monitoring the leakage of hydrogen gas on account of its fast color change in contact with hydrogen gas. However, for the practical application of the sensor, such as in gas detection systems in clothing, the flexibility and stability of the sensor need to be improved. Here, we present a novel method to fabricate a flexible colorimetric hydrogen sensor with the stable embedment of sensing material. To improve the flexibility and stability of the sensor, polyacrylonitrile nanofiber containing palladium oxide and zinc oxide hybrid nanoparticles was prepared by electrospinning. The flexible colorimetric hydrogen sensor can detect 1000 ppm hydrogen gas with excellent selectivity within 2 min. We also suggest film and yarn-type flexible colorimetric hydrogen sensors for industrial and wearable applications. A laminating process was used to prepare the film. In contrast, twisting and polydimethylsiloxane coating were used to prepare the yarn-type flexible colorimetric hydrogen sensor. Compared with a flexible colorimetric hydrogen-sensing nanofiber, the film and yarn show identical sensitivity for detecting a hydrogen leakage. These applications of hydrogen sensors could be a new insight into the design of a flexible sensor for detecting hydrogen leakage with the naked eye.

Sign in / Sign up

Export Citation Format

Share Document