Design and Fabrication of High Vacuum Gauge Based on Micro Hotplate

2015 ◽  
Vol 645-646 ◽  
pp. 698-705 ◽  
Author(s):  
Feng Tian Zhang ◽  
Ying Bin Zheng ◽  
Bin Tang ◽  
Wei Su ◽  
Zhen’an Tang
Keyword(s):  
Heat Conduction ◽  
Heat Dissipation ◽  
High Vacuum ◽  
High Sensitivity ◽  
Response Speed ◽  
Fast Response ◽  
Measurement Range ◽  
Heat Radiation ◽  
Vacuum System ◽  
Vacuum Gauge

Vacuum gauge based on micro hotplate (MHP) is a kind of promising MEMS vacuum gauge due to its advantages including high sensitivity, wide measurement range, fast response speed and comparably easy fabrication, etc. In this paper, through analyzing various of heat dissipation approaches including solid heat conduction, gas heat conduction, heat radiation, and convection, the sensor output expression of MHP-based vacuum gauge is obtained when keeping electric current of heating resistor constant. With the structure size and material properties, the relationship curve between vacuum gauge output and gas pressure can be obtained. By wet etching silicon under the compound dielectric films with embedded metal film resistor, MHP suspended over silicon substrate is fabricated. Then the sensor chip is assembled and put into vacuum system, and test is conducted when keeping the heating resistor at constant heating current of 5mA. The measurement results show that the sensor measurement range is 5×10-3Pa~103Pa, which is basically consistent with the theoretical analyzing results.

scholarly journals Tin Disulfide-Coated Microfiber for Humidity Sensing with Fast Response and High Sensitivity

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 648
Author(s):  
Aijie Liang ◽  
Jingyuan Ming ◽  
Wenguo Zhu ◽  
Heyuan Guan ◽  
Xinyang Han ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
Small Diameter ◽  
High Sensitivity ◽  
Large Change ◽  
Small Variation ◽  
Response Speed ◽  
Fast Response ◽  
Tin Disulfide ◽  
Recovery Times ◽  
Response And Recovery

Breath monitoring is significant in assessing human body conditions, such as cardiac and pulmonary symptoms. Optical fiber-based sensors have attracted much attention since they are immune to electromagnetic radiation, thus are safe for patients. Here, a microfiber (MF) humidity sensor is fabricated by coating tin disulfide (SnS2) nanosheets onto the surface of MF. The small diameter (~8 μm) and the long length (~5 mm) of the MF promise strong interaction between guiding light and SnS2. Thus, a small variation in the relative humidity (RH) will lead to a large change in optical transmitted power. A high RH sensitivity of 0.57 dB/%RH is therefore achieved. The response and recovery times are estimated to be 0.08 and 0.28 s, respectively. The high sensitivity and fast response speed enable our SnS2-MF sensor to monitor human breath in real time.

Eine Methode zur Messung geringster Ölbedeckungen in Vakuumsystemen

1967 ◽  
Vol 22 (4) ◽  
pp. 549-553 ◽  
Author(s):  
R. Dobrozemsky ◽  
W. K. Huber ◽  
F. Viehböck
Keyword(s):  
High Vacuum ◽  
High Sensitivity ◽  
Radioactive Tracer ◽  
Operating Conditions ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
First Results ◽  
Tracer Isotope ◽  
Radioactive Tracer Method ◽  
Vacuum Systems

To get information on extremely small organic deposits in ultra high vacuum systems the sensitivity of most of the conventional methods for thickness measurements is not high enough. On the other hand the radioactive tracer method has shown its high sensitivity and wide versatility in many fields. Tritium with a half life of 12.3 γ and a mean β-energy of 5.4 keV was choosen as tracer isotope. A method is described for Tritium-labelling diffusion pump oils with specific activities up to 100 mC/g. Using the liquid scintillation counting technique one can detect deposits down to below 1010 molecules/cm2. First results with this Tritium labelled pump fluid are given under different operating conditions in an all metal ultra high vacuum system.

Verification and Design of High Precision Eddy Current Sensor for Tip Clearance Measurement

2018 ◽  
Author(s):  
Ziyu Zhao ◽  
Zhenxia Liu ◽  
Yaguo Lyu ◽  
Xinxin Xu
Keyword(s):  
High Precision ◽  
Eddy Current ◽  
High Sensitivity ◽  
Response Speed ◽  
Measurement Range ◽  
Tip Clearance ◽  
Current Sensor ◽  
Eddy Current Sensor ◽  
Planar Coil ◽  
Sensor Coil

A high precision eddy current sensor for tip clearance measurement was proposed to assess the dynamic tip clearance measurement for aero-engine rotator. Based on the Lenz’s law, the eddy current sensor has high sensitivity, quick response speed and strong anti-interference capability, in addition, the simple geometry and easy installation are its main merits. The aim is to study the influence of planar coil structure parameters and excitation signal parameters on the sensor coil measurement, provide the basis for design of practical sensor in turbine tip clearance measurement. The dynamic calibration experiment verified the designed planar sensor coil, the results indicated the sensor resolution was 10μm and the measurement range was not less than 3mm. The dynamic experiment proved the measuring range, resolution, response speed of designed sensor can meet the requirement of turbine blade tip clearance measurement. The work provides experience in eddy current sensor design in different application, not only in turbine. And the future work will focus on the high temperature issues.

Microfabrication of Thermoelectric Hydrogen Sensor Using KOH Solution Etching

2006 ◽  
Vol 301 ◽  
pp. 273-276 ◽  
Author(s):  
Kazuki Tajima ◽  
Yeong Soo Choi ◽  
Woosuck Shin ◽  
Noriya Izu ◽  
Ichiro Matsubara ◽  
...  
Keyword(s):  
Integrated Circuit ◽  
Hydrogen Oxidation ◽  
Exothermic Reaction ◽  
High Sensitivity ◽  
Response Speed ◽  
Hydrogen Sensor ◽  
Fast Response ◽  
Sensor Technology ◽  
Circuit Fabrication ◽  
Voltage Signal

Micromachined sensors are a new generation of sensor technology combining existing integrated circuit fabrication technology with novel deposition and etching processing. In the viewpoint of low-power operation, high sensitivity and fast response speed of thermoelectric hydrogen sensor (THS), we prepared the micromachined thermoelectric hydrogen sensor (micro-THS) with the combination of the thermoelectric effect of SiGe thin film and the Pt-catalyzed exothermic reaction of hydrogen oxidation. The power consumption of the micro-THS was greatly reduced to be 50 mW for 100 °C operating, by the Pt-micro-heater on single membrane. The micro-THS with 40 wt.% Pt/alumina catalyst showed voltage signal of 10 mV for 1 % H2 in air.

A graphene/GaAs near-infrared photodetector enabled by interfacial passivation with fast response and high sensitivity

2015 ◽  
Vol 3 (18) ◽  
pp. 4723-4728 ◽  
Author(s):  
Lin-Bao Luo ◽  
Han Hu ◽  
Xian-He Wang ◽  
Rui Lu ◽  
Yi-Feng Zou ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Sensitivity ◽  
Response Speed ◽  
Fast Response ◽  
Device Performance ◽  
Infrared Photodetector

We report on a simple passivation strategy to improve the device performance of a near infrared (NIR) photodetector. Optoelectronic analysis reveals that after ultrathin AlOxpassivation, the device exhibits an obvious increase in on/off ratio. What is more, the response speed of the device was improved by more than 100 times, from 48 μs to 380 ns.

scholarly journals A Strategy for High-Performance Photodetector based on Graphene-Si heterostructure

2020 ◽  
Vol 213 ◽  
pp. 02014
Author(s):  
Tianying He ◽  
Changyong Lan ◽  
Chun Li ◽  
Sihan Zhou ◽  
Yi Yin
Keyword(s):  
High Performance ◽  
Collection Efficiency ◽  
Van Der Waals ◽  
High Sensitivity ◽  
Response Speed ◽  
Fast Response ◽  
Van Der Waals Heterostructure ◽  
Mapping Technology ◽  
Peak Sensitivity ◽  
Heterostructure Devices

Van der Waals heterostructure shows promising applications in next generation optoelectronics. As a kind of van der Waals heterostructure, graphene/silicon (Gr/Si) based heterostructure devices have been demonstrated as high performance photodetectors. Here, we studied the origin of the high performance of Gr/Si photodetectors based on photocurrent mapping technology. According to photocurrent mapping, the photocurrent in the Gr/Si and Gr/SiO2/Si area nearing the Si window edge is higher than that in other positions, which is attributed to the highly effective collection efficiency of photocarriers. A device with size of Gr/Si region (r=7.4 μm) and Gr/SiO2/Si region (L=6.1 μm) shows high sensitivity and a broadband photoresponse in the range from 420 to 1000 nm with the peak sensitivity of 52 A/W at 780 nm, and fast response speed with rise time of 16 μs and decay time of 52 μs. Our study provides a strategy for the design of high photoresponsivity Gr/Si based devices.

scholarly journals Theoretical Study on Characteristics of Glow Discharged Neon Gas and Its Interaction With Terahertz Waves

2021 ◽  
Vol 9 ◽  
Author(s):  
Lei Hou ◽  
Yaodong Wang ◽  
Junnan Wang ◽  
Lei Yang ◽  
Wei Shi
Keyword(s):  
Room Temperature ◽  
High Sensitivity ◽  
Response Speed ◽  
Fast Response ◽  
Terahertz Waves ◽  
Thz Wave ◽  
Wave Detector ◽  
Discharge Model ◽  
Neon Glow Discharge ◽  
Thz Waves

Discharge gases have been used to detect terahertz (THz) waves, however, there are few relevant theoretical studies. The neon glow discharge model is established by COMSOL Multiphysics software, the characteristics of glow discharged neon and the interaction of the discharged gas with THz waves were investigated. The results show that with the increase of THz wave’s frequency, the transmittance increases, the change of plasma discharge characteristics caused by THz wave can be used for THz wave detection. The results provide a theoretical basis for the development of cheap, room temperature THz wave detector with fast response speed, and high sensitivity.

Small-diameter p-type SnS nanowire photodetectors and phototransistors with low-noise and high-performance

2021 ◽  
Author(s):  
Ruoling Chen ◽  
Long Li ◽  
Long Jiang ◽  
Xiangxiang Yu ◽  
Desheng Zhu ◽  
...  
Keyword(s):  
Low Power ◽  
Dark Current ◽  
High Performance ◽  
Wide Spectrum ◽  
Small Diameter ◽  
High Sensitivity ◽  
Response Speed ◽  
Fast Response ◽  
Low Noise ◽  
P Type

Abstract P-type nanostructured photodetectors and phototransistors have been widely used in the field of photodetection due to their excellent electrical and optoelectronic characteristics. However, the large dark current of p-type photodetectors will limit the detectivity. Herein, we synthesized small-diameter single-crystalline p-type SnS nanowires (NWs) and then fabricated single SnS NW photodetectors and phototransistors. The device exhibits low noise and low dark current, and its noise current power is as low as 2.4 × 10−28 A2. Under 830 nm illumination and low power density of 0.12 mW cm2, the photoconductive gain, responsivity and detectivity of the photodetector are as high as 3.9 × 102, 2.6 × 102 A W−1 and 1.8 × 1013 Jones, respectively, at zero gate voltage. The rise and fall time of response are about 9.6 and 14 ms. The experimental results show that the small-diameter p-type SnS NWs have broad application prospects in high-performance and low-power photodetectors with high sensitivity, fast response speed and wide spectrum detection in the future.

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