Studies on Thin Films (Dielectric and Metallic) Constituting Micro Thermo-Mechanical Sensors Embedded in Metal Structures

2004 ◽  
Author(s):  
Arindom Datta ◽  
Hongseok Choi ◽  
Xiaochun Li
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Metal Structure ◽  
Fast Response ◽  
Metal Substrate ◽  
Strain Gages ◽  
Structural Components ◽  
Metal Structures ◽  
Thin Film Thermocouples ◽  
Mechanical Sensors

It is of interest to obtain the thermomechanical response of tools, equipment, and structural components in a real manufacturing environment. Microfabricated thin film thermocouples and strain gages are attractive for their small size and fast response. It is novel and challenging to fabricate these sensors on metal substrate and finally embed them into location of interest. Consequently, the materials (dielectric and metallic) constituting the sensor need to be characterized and optimized properly for reliability. We present here results of characterization and optimization of materials making a thermomechanical sensor to be embedded in metal structure.

Development of High-Efficiency Zn2SiO4:Mn Thin Films for Flat Panel Cathodoluminescent Displays

1997 ◽  
Vol 471 ◽  
Author(s):  
J. Liu ◽  
D. C. Morton ◽  
M. R. Miller ◽  
Y. Li ◽  
E. W. Forsythe ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Conductivity ◽  
Response Time ◽  
Decay Time ◽  
High Efficiency ◽  
Fast Response ◽  
Flat Panel ◽  
Powder Phosphor ◽  
Fast Response Time

ABSTRACTZn2SiO4:Mn thin films were deposited and studied as thin film phosphors for flat panel cathodoluminescent displays. Crystallized films with improved electrical conductivity were obtained after conventional and rapid thermal annealings in a N2 environment at 850Xy11100 °C for 0.25 to 60 minutes. A maximum cathodoluminescent efficiency of 1.3 Lm/W was achieved under dc excitation at 1500 volts. The luminescent emission from these thin films was peaked around 525 nm. The decay time of these films was controlled in the range of 2 to 10 ms by varying the deposition and annealing parameters. The fast response time of these thin films overcomes the long decay limitation of the Zn2SiO4:Mn powder phosphor in practical display applications.

Enhanced UV Photon-response of Tin Nano Cluster Loaded- laser Irradiated ZnO Thin film detector

2011 ◽  
Vol 1288 ◽  
Author(s):  
Rashmi Menon ◽  
K. Sreenivas ◽  
Vinay Gupta
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetron Sputtering ◽  
Surface States ◽  
Response Speed ◽  
Rf Magnetron Sputtering ◽  
Fast Response ◽  
Zno Thin Films ◽  
Zno Thin Film ◽  
Photo Response

ABSTRACTZinc Oxide (ZnO), II-VI compound semiconductor, is a promising material for ultraviolet (UV) photon sensor applications due to its attractive properties such as good photoconductivity, ease processing at low temperatures and excellent radiation hardness. The rf magnetron sputtering is a suitable deposition technique due to better control over stoichiometry and deposition of uniform film. Studies have shown that the presence of surface defects in ZnO and subsequently their passivation are crucial for enhanced photo-response characteristics, and to obtain the fast response speed. Worldwide efforts are continuing to develop good quality ZnO thin films with novel design structures for realization of an efficient UV photon sensor. In the present work, UV photon sensor is fabricated using a ZnO thin films deposited by rf magnetron sputtering on the corning glass substrate. Photo-response, (Ion/Ioff) of as-grown ZnO film of thickness 100 nm is found to be 3×103 with response time of 90 ms for UV intensity of 140 μW/cm2 (λ = 365 nm). With irradiation on ZnO thin film by pulsed Nd:YAG laser (forth harmonics 266 nm), the sensitivity of the UV sensor is found to enhance. The photo-response increases after laser irradiation to 4x104 with a fast response speed of 35 ms and attributed to the change in surface states and the native defects in the ZnO thin film. Further, enhancement in the ultraviolet (UV) photo-response (8×104) of detector was observed after integrating the nano-scale islands of Sn metal on the surface of laser irradiated ZnO thin film.

Cycling Times of Thin-Film NiTi on Si

1991 ◽  
Vol 246 ◽  
Author(s):  
A. Peter Jardine
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Response Times ◽  
Bulk Material ◽  
Fast Response ◽  
Promising Candidate ◽  
Strain Measurements ◽  
Micro Actuator ◽  
Acoustic Velocities

AbstractThe thermo-mechanical properties of NiTi are well known for bulk material although its deposition and utilization as a thin film are still in their earliest stages. The deposition of thin-films of Shape Memory Effect NiTi onto Si(100) wafers offers several advantages over bulk NiTi, including fast response times and comparitively large transformation forces, and so is a promising candidate as a micro-actuator for MicroElectroMechanical (MEMS) systems as well as in strain measurements. The response time for a variety of NiTi layers were modelled under different boundary conditions and show response times similar to the acoustic velocities for one micron thick NiTi.

Micro Thin Film Temperature Sensors Embedded in Metal Structures

2004 ◽  
Author(s):  
Hongseok Choi ◽  
Arindom Datta ◽  
Xiaochun Li
Keyword(s):  
Thin Film ◽  
Chemical Vapor ◽  
Temperature Sensors ◽  
In Situ Monitoring ◽  
Manufacturing Processes ◽  
Metal Structures ◽  
Thin Film Sensors ◽  
Thin Film Thermocouple ◽  
Thin Film Thermocouples

This paper studies the fabrication and calibration of thin film temperature sensors embedded in metal structures. Thin film thermocouples have been successfully fabricated on various metal substrates and advanced embedding techniques have been developed to ensure sensor function inside metal structures. Thin film thermocouple was insulated with multiple thin film layers (Al2O3 and Si3N4) by e-beam evaporating and plasma enhanced chemical vapor deposition (PECVD). The sensors are calibrated. These embedded thin film sensors provide superior spatial and temporal resolution that is not possible with traditional sensors used in various manufacturing processes. This research is significant in a way that it provides a new and improved route for in-situ monitoring of manufacturing process.

Embedded Piezoresistive Thin Films for Monitoring GFRP Composites

2010 ◽  
Author(s):  
Bryan R. Loyola ◽  
Valeria La Saponara ◽  
Kenneth J. Loh
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Damage Detection ◽  
Glass Fiber ◽  
Electrical Impedance Spectroscopy ◽  
Detection Sensitivity ◽  
Strain Sensitivity ◽  
Structural Components ◽  
Fiber Reinforced ◽  
Embedded Sensing

The trend towards higher reliance on fiber-reinforced composites for structural components has led to the need to rethink current nondestructive evaluation (NDE) strategies. In principle, embeddable sensor schemes are desired for green-light/red-light structural health monitoring systems that do not negatively affect the properties and performance of the host structure. However, there are still numerous challenges that need to be overcome before these embedded sensing technologies can be realized for real-world structural systems. For example, some of these issues and challenges include the damage detection sensitivity/threshold, reliability of the system, transportability of the system to multiple configurations and different types of structural components, and signal processing/interpretation. The objective of this study is to develop a novel, embedded sensing system that can accurately quantify damage to composites without interfering with structural performance and functionality. In particular, this study will utilize multi-walled carbon nanotube (MWNT)-polyelectrolyte (PE) thin films deposited on a glass fiber substrate for in situ composite structural monitoring. A layer-by-layer (LbL) film fabrication methodology is employed for depositing piezoresistive nanocomposites directly onto glass fiber fabrics, and the resulting film exhibits excellent strain sensing performance, homogeneity, and exhibits no phase segregation. Specifically, the LbL fabrication process will employ polycationic poly(vinyl alcohol) (PVA) and polyanionic poly(sodium 4-styrene sulfonate) (PSS) doped with MWNTs for fabricating the electrically-conductive and piezoresistive thin films. Upon film deposition, the glass fiber substrates are infused with an epoxy matrix via wet-layup to fabricate self-sensing glass fiber-reinforced polymer (GFRP) composite specimens for testing. A frequency-domain approach, based on electrical impedance spectroscopy, is used to characterize the electromechanical response of the GFRP-MWNT-based thin film samples when subjected to complex uni-axial tensile load patterns. A resistor connected to a parallel resistor-capacitor circuit model is proposed for fitting experimental impedance spectroscopic measurements. It has been found that the series resistor models the bulk thin film piezoresistive performance accurately. In addition, these impedance measurements shed light on the glass fiber-thin film interaction electromechanical behavior. Bi-functional strain sensitivity is observed for all GFRP specimens, and the transition point of bilinear strain sensitivity is utilized as a possible metric for GFRP damage detection.

scholarly journals Effects of AlN and BCN Thin Film Multilayer Design on the Reaction Time of Ni/Ni-20Cr Thin Film Thermocouples on Thermally Sprayed Al2O3

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3414
Author(s):  
Tillmann ◽  
Kokalj ◽  
Stangier ◽  
Schöppner ◽  
Malatyali
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Reaction Time ◽  
Seebeck Coefficient ◽  
Physical Structure ◽  
Boron Carbonitride ◽  
Deposition Parameters ◽  
Thin Film Thermocouples ◽  
Nitride Layers ◽  
The Impact

Thin film thermocouples are widely used for local temperature determinations of surfaces. However, depending on the environment in which they are used, thin film thermocouples need to be covered by a wear or oxidation resistant top layer. With regard to the utilization in wide-slit nozzles for plastic extrusion, Ni/Ni-20Cr thin film thermocouples were manufactured using direct-current (DC) magnetron sputtering combined with Aluminiumnitride (AlN) and Boron-Carbonitride (BCN) thin films. On the one hand, the deposition parameters of the nitride layers were varied to affect the chemical composition and morphology of the AlN and BCN thin films. On the other hand, the position of the nitride layers (below the thermocouple, above the thermocouple, around the thermocouple) was changed. Both factors were investigated concerning the influence on the Seebeck coefficient and the reaction behaviour of the thermocouples. Therefore, the impact of the nitride thin films on the morphology, physical structure, crystallite size, electrical resistance and hardness of the Ni and Ni-20Cr thin films is analysed. The investigations reveal that the Seebeck coefficient is not affected by the different architectures of the thermocouples. Nevertheless, the reaction time of the thermocouples can be significantly improved by adding a thermal conductive top coat over the thin films, whereas the top coat should have a coarse structure and low nitrogen content.

scholarly journals Synthesis and Characterizations of Cu Doped Co3O4 Nanostructured Thin Films Using Spray Pyrolysis for Glucose Sensor Applications

2021 ◽  
Vol 12 (5) ◽  
pp. 6321-6335
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Spray Pyrolysis ◽  
Glucose Sensor ◽  
Spray Pyrolysis Technique ◽  
Fast Response ◽  
Glucose Sensing ◽  
Sem Images ◽  
Cu Doping ◽  
Sensing Properties

Nanostructured cobalt oxide (Co3O4) and Cu-doped Co3O4 thin films were synthesized by a simple spray pyrolysis technique at 450oC substrate temperature onto the plain glass substrate. The surface morphological, structural, optical, electronic, and glucose sensing effects of the deposited thin films were explored. Scanning Electron Microscope (SEM) images revealed a uniform, dense and porous surface morphology of Co3O4 and Cu doped Co3O4 thin films. X-ray diffraction (XRD) pattern showed the spinel cubic structure of lattice parameters a = b = c = 8.0764 Å and well agrees with the JCPDS card file no. 42-1467. The crystallite sizes were calculated as 29, 27, 24, and 26 nm with the variation of 0, 2, 4, and 6 % Cu doping concentrations, respectively. The obtained optical band gaps were about 2.02, 2.00, 2.09, and 1.98 eV for 0, 2, 4, and 6 % Cu doped Co3O4 thin films. The glucose sensing properties revealed that Cu doping greatly improved the sensing properties of Co3O4 thin film, and the highest glucose sensitivity was found at about 43%, and fast response time was about 0.97 sec at 4 % Cu doped Co3O4 thin-film.

scholarly journals Recent advances in Performance and effect of Zr doping with ZnO thin film sensor in Ammonia Vapour Sensing

2021 ◽  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Gas Sensing ◽  
Wide Band ◽  
Fast Response ◽  
Sem Analysis ◽  
Zno Thin Film ◽  
Film Sensor ◽  
Doped Zno ◽  
Silar Technique

<p>Pure and Zr doped ZnO thin films were prepared using SILAR technique. The influence of Zr doping on structural, morphological, optical and gas sensing properties of ZnO has been reported. X-ray diffraction study confirmed the formation of wurtzite structure of ZnO thin film (JCPDS 36-1451) fabricated by SILAR technique and the caluculated crystallites size of pure and doped ZnO were 39 and 36 nm respectively . SEM analysis of thin films has shown a completely different surface morphology. EDAX spetrum cnfirmed the presence of different compositional element in the fabriated thin films. Zr (3 wt%) doped ZnO thin film exhibited the best properties with a good transmittance and it has wide band gap of 3.26 eV. Photoluminescence emissions indicated increase in concentration of oxygen vacancies with introduction of dopant. NH3 vapour sensors were fabricated out of fabricated samples and it was observed that doped samples have significantly high sensing response, good selectivity, fast response and recovery time to ammonia vapoutr at room temperature.</p>

scholarly journals Fast Response Solar-Blind Photodetector with a Quasi-Zener Tunneling Effect Based on Amorphous In-Doped Ga2O3 Thin Films

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 129 ◽  
Author(s):  
Mingzhi Fang ◽  
Weiguo Zhao ◽  
Feifei Li ◽  
Deliang Zhu ◽  
Shun Han ◽  
...  
Keyword(s):  
Thin Films ◽  
Positive Impact ◽  
Metal Structure ◽  
Fast Response ◽  
Tunneling Effect ◽  
Detection Range ◽  
High Responsivity ◽  
Internal Gain ◽  
Solar Blind ◽  
Zener Tunneling

A high-performance solar-blind photodetector with a metal–semiconductor–metal structure was fabricated based on amorphous In-doped Ga2O3 thin films prepared at room temperature by radio frequency magnetron sputtering. The photodetector shows a high responsivity (18.06 A/W) at 235 nm with a fast rise time (4.9 μs) and a rapid decay time (230 μs). The detection range was broadened compared with an individual Ga2O3 photodetector because of In doping. In addition, the uneven In distribution at different areas in the film results in different resistances, which causes a quasi-Zener tunneling internal gain mechanism. The quasi-Zener tunneling internal gain mechanism has a positive impact on the fast response speed and high responsivity.

Design of Micro-Arrayed Thin Film Thermocouples (TFTC)

2003 ◽  
Author(s):  
Jong-Jin Park ◽  
Minoru Taya
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Heat Conduction ◽  
Steady State ◽  
Aluminum Nitride ◽  
Silicon Wafer ◽  
Measured Data ◽  
Bulk Materials ◽  
Thin Aluminum ◽  
Thin Film Thermocouples

We designed the thin film thermocouples (TFTC) made by T-type (Copper-Constantan) thermocouple arrays in order to measure temperature distribution at higher spatial resolutions. This sensor consists of a few different layers; silicon wafer, thin aluminum nitride (AlN) layer, and thin film thermocouple layers. The thickness of the thin aluminum nitride (AlN) layer is 100nm and the layer is located between silicon wafer and thin film thermocouples to construct an electrical insulator and thermal conductor. T-type (Copper-Constantan) thermocouples are deposited on the aluminum nitride (AlN) layer over the silicon wafer and the copper thickness and constantan thickness are 50nm, repectively. The sensor area is 10mm × 10mm, and has 10 × 10 junction arrays, and each junction has 100μm × 100μm surface area. According to the measured data, electrical resistivitives of thin films are almost 5 times greater than those of bulk materials. This is based on the comparison of thermal simulation and measured data of 1-D heat conduction in steady state. Seebeck coefficients between copper bulk material and constantan thin film are calculated and the weight factor is defined due to Seebeck coefficient mismatches of bulk materials and thin films. Thermal simulation of 2-dimensional heat conduction in steady state calculated by finite element analysis and compared with the measured data, resulting in a good agreement between simulations and measured data.

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