Design, fabrication and characterization of metal embedded thin film thermocouples with various film thicknesses and junction sizes

Zhang, Xugang; Choi, Hongseok; Datta, Aniruddha; Li, Xiaochun

doi:10.1088/0960-1317/16/5/004

Cited by 79 publications

(33 citation statements)

References 11 publications

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“…In a calibration experiment with these two types of probes, we found that the 100 nm probe produced a temperature-thermoelectricity curve that showed an almost perfect match with the standard curve produced by a regular macro-sized TC, while the readings from the 50 nm probe showed deviations from the standard curve ( Figure 1B and 1C and Supplementary information, Figure S2). This result is consistent with earlier reports that when the thickness of the Pt film decreases beyond the 100 nm range, it will affect the resulting thermoelectric power compared to the macrosized TC at the same temperature [6,7]. Thus, we have chosen the 100 nm probe in further experiments.…”

supporting

confidence: 89%

Determining intracellular temperature at single-cell level by a novel thermocouple method

et al. 2011

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Living cells can change their intramembranous temperature during cell activities such as division, gene expression, enzyme reaction, and metabolism [1,2]. Moreover, under external stimuli, such as drugs or other signals, cells may quickly change their metabolic activities, leading to acute variation of intracellular temperatures from the normal state [3,4]. However, such temperature change inside cells is usually at a small scale and is of transient nature due to the thermo-influence by the extracellular environment, rendering it rather difficult to measure using the conventional temperature detection methods. Thus, a more precise and faster-response thermometer is needed to measure single-cell temperature changes in real time, which may constitute a new layer of cellular information for studies of cellular signaling, and even clinical diagnosis and therapy.Fluorescent nanogel has been previously applied to detect changes in intracellular temperature [4]. Cells were first allowed to take up a fluorescence material and the average intracellular temperature change under a certain treatment was then determined through measuring the distinct fluorescent light intensity before and after the treatment. Such a fluorescent nanogel-based method has a number of disadvantages, including potential toxicity to cells, limit of measurement resolution (generally in the range of 0.29 °C-0.50 °C), and limit of time-scale resolution (at the scale of minutes).Thermocouple (TC) is widely used in settings that require detection of temperature changes. The TC-based detection method has a number of advantages, including the capacity for achieving high precision and rapid response. To adapt the TC method for temperature measurement at the single-cell level, one would need to develop a micro-sized TC probe (at sub-micrometer scale). The thin film method is a common approach to producing two-dimensional micro-or even nano-TCs for use in electronics industry [5]. However, such two-dimensional TCs that rely on the support of silicon chips cannot be readily used for measuring intracellular temperature. In this report, we designed a novel TC device for detecting intracellular temperature ( Figure 1A and 1B). Briefly, our TC probe is made of a sandwich structure consisting of the tungsten (W) substrate, an insulating layer made of polyurethane (PU; except at the tip), and a platinum (Pt) film (Supplementary information, Figure S1). We produced two types of TC probes, with different thickness of the Pt film (50 nm and 100 nm). In a calibration experiment with these two types of probes, we found that the 100 nm probe produced a temperature-thermoelectricity curve that showed an almost perfect match with the standard curve produced by a regular macro-sized TC, while the readings from the 50 nm probe showed deviations from the standard curve ( Figure 1B and 1C and Supplementary information, Figure S2). This result is consistent with earlier reports that when the thickness of the Pt film decreases beyond the 100 nm range, it will affect the resulti...

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supporting

confidence: 89%

Determining intracellular temperature at single-cell level by a novel thermocouple method

et al. 2011

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“…Recently, thermomechanical phenomena were studied by the use of embedded thin-film sensors for various manufacturing processes [18][19][20][21][22][23][24]. Two types of thin-film microsensors, K-type TFTC, and K-type thermocouple based TETP, were designed and fabricated for in-situ temperature measurement of ultrasonic welding process to better understand the process [18,22].…”

Section: Introductionmentioning

confidence: 99%

Transient Temperature and Heat Flux Measurement in Ultrasonic Joining of Battery Tabs Using Thin-Film Microsensors

Li¹,

Choi²,

Ma³

et al. 2013

Journal of Manufacturing Science and Engineering

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Process physics understanding, real time monitoring, and control of various manufacturing processes, such as battery manufacturing, are crucial for product quality assurance. While ultrasonic welding has been used for joining batteries in electric vehicles (EVs), the welding physics, and process attributes, such as the heat generation and heat flow during the joining process, is still not well understood leading to time-consuming trial-and-error based process optimization. This study is to investigate thermal phenomena (i.e., transient temperature and heat flux) by using micro thin-film thermocouples (TETC) and thin-film thermopile (TETP) arrays (referred to as microsensors in this paper) at the very vicinity of the ultrasonic welding spot during joining of three-layered battery tabs and Cu buss bars (i.e., battery interconnect) as in General Motors's (GM) Chevy Volt. Microsensors were first fabricated on the buss bars. A series of experiments were then conducted to investigate the dynamic heat generation during the welding process. Experimental results showed that TETCs enabled the sensing of transient temperatures with much higher spatial and temporal resolutions than conventional thermocouples. It was further found that the TETPs were more sensitive to the transient heat generation process during welding than TETCs. More significantly, the heat flux change rate was found to be able to provide better insight for the process. It provided evidence indicating that the ultrasonic welding process involves three distinct stages, i.e., friction heating, plastic work, and diffusion bonding stages. The heat flux change rate thus has significant potential to identify the insitu welding quality, in the context of welding process monitoring, and control of ultrasonic welding process. The weld samples were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to study the material interactions at the bonding interface as a function of weld time and have successfully validated the proposed three-stage welding theory.

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“…Film thickness is a critical parameter that influences the sensitivity of TFT [21]- [23]. However, the sensitivity of K-type thin-film thermocouples is independent of the film thickness when the it is greater than140nm [24]. 16 cycles of sputter deposition with sputter current of 150mA and cycle time of 120S could yield films with thicknesses sufficiently greater than this threshold.…”

Section: B Sensor Fabricationmentioning

confidence: 99%

Cell integrated thin-film multi-junction thermocouple array for in-situ temperature monitoring of solid oxide fuel cells

2015

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Design, fabrication and characterization of metal embedded thin film thermocouples with various film thicknesses and junction sizes

Cited by 79 publications

References 11 publications

Determining intracellular temperature at single-cell level by a novel thermocouple method

Determining intracellular temperature at single-cell level by a novel thermocouple method

Transient Temperature and Heat Flux Measurement in Ultrasonic Joining of Battery Tabs Using Thin-Film Microsensors

Cell integrated thin-film multi-junction thermocouple array for in-situ temperature monitoring of solid oxide fuel cells

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