An Ultrafast Thin-Film Microcalorimeter with Monola Yer Sensitivity (J/m2)

1995 ◽  
Vol 398 ◽  
Author(s):  
S.L. Lai ◽  
P. Infante ◽  
G. Ramanath ◽  
L.H. Allen
Keyword(s):  
Thin Film ◽  
Heating Rate ◽  
Current Pulse ◽  
High Sensitivity ◽  
Melting Process ◽  
Thermal Mass ◽  
Calorimetric Measurements ◽  
Calorimetric Technique ◽  
Dc Current ◽  
Thin Film Membrane

ABSTRACTWe introduce a high-sensitivity (∼1 J/m2) scanning microcalorimeter that can be used to perform direct calorimetric measurements on thin film samples at ultrafast heating rate (∼104 °C/s). This novel microcalorimeter is fabricated by utilizing SiN thin-film membrane technology, resulting in dramatically reduced thermal mass of the system. Calorimetric measurements are accomplished by applying a dc-current pulse to the thin-film metal (Ni) heater which also serves as a thermometer, and monitoring the real-time voltage and current of the heater. The temperature of the system and the energy delivered to the system are then determined. This calorimetric technique has been demonstrated by measuring the melting process of thin Sn films with thickness ranging from 13 to 1000 Å, and shows potential for calorimetric probing of irreversible reactions at interfaces and surfaces, as well as transformations in nanostructured materials.

Microreactors for Thin-Film Calorimetry

2002 ◽  
Vol 741 ◽  
Author(s):  
J. Rodríguez-Viejo ◽  
M. Chacón ◽  
A.F. Lopeandía ◽  
M.T. Clavaguera-Mora ◽  
Leonel R. Arana ◽  
...  
Keyword(s):  
Heat Capacity ◽  
High Vacuum ◽  
Transient State ◽  
High Sensitivity ◽  
Symmetric Design ◽  
Input Power ◽  
Cdse Nanocrystals ◽  
Thermal Mass ◽  
Heating Rates ◽  
Calorimetric Measurements

ABSTRACTWe have designed and developed a calorimeter that is capable of measuring the heat released by ultrathin films in the temperature range from 77 to 1050 K. Semiconductor processing techniques are used to fabricate the microreactors. The symmetric design of the Pt heaters in the microreactor channel provide a good temperature profile across the active region of the membrane making it suitable for accurate calorimetric measurements. The low thermal mass of our system allows for a high sensitivity. The effective heat capacity of the microcalorimeters with a 200 nm SixNy membrane is 0.14 μJ/K at room temperature. In high vacuum heating rates of 2×106 K/s have been achieved. Under these conditions the microcalorimeter works as an adiabatic scanning calorimeter and therefore heat capacity is directly obtained from the input power. A thermal characterization of the microcalorimeters in the transient state and calorimetric measurements on indium thin films and films made of CdSe nanocrystals are briefly discussed to show the potentiality of the microreactors.

High Sensitivity pH Sensors based on Amorphous Indium-gallium-zinc Oxide Thin-film Transistors

2015 ◽  
Vol 135 (6) ◽  
pp. 192-198 ◽  
Author(s):  
Shinnosuke Iwamatsu ◽  
Yutaka Abe ◽  
Toru Yahagi ◽  
Seiya Kobayashi ◽  
Kazushige Takechi ◽  
...  
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Thin Film Transistors ◽  
High Sensitivity ◽  
Oxide Thin Film ◽  
Indium Gallium Zinc Oxide ◽  
Ph Sensors ◽  
Zinc Oxide Thin Film ◽  
Indium Gallium

Investigation of Nanometric Thin-Film Bismuth Piezoresistors Deposited on Silicon Substrates

2012 ◽  
Vol 1477 ◽  
Author(s):  
Horacio V. Estrada
Keyword(s):  
Thin Film ◽  
Axial Strain ◽  
High Sensitivity ◽  
Metal Alloys ◽  
Silicon Substrates ◽  
Transverse Strain ◽  
Bending Stress ◽  
Pure Bending ◽  
Strain Fields ◽  
Strain Axis

ABSTRACTThin film bismuth piezoresistors, defined on oxidized silicon wafers, are investigated as a function of their orientation for their eventual integration on micro-electro-mechanical (MEMS) microsensors. Bismuth’s piezoresistance (or elasto-resistance) is experimentally investigated to accurately determine its longitudinal and transverse strain sensitivities. Whisker-shaped resistive elements defined on different orientations (from 0o, the beam’s main strain axis, to 90o, perpendicular to that axis) undergo changes of resistance (ΔR), associated with the induced strains on silicon cantilevers beam’s surface when these are mechanically loaded under pure bending stress conditions. For Bi-resistors, the traditional gage factor concept, (ΔR/Ro)/εl, is found to be equal to +16 and +33, for elements oriented along 0 and 90o, respectively, considerably larger than those for metals or metal alloys. These high sensitivity values and the “unusual” positive, higher value for the 90o (perpendicular) resistors can be of considerable interest for microsensors applications. The results of this study enable us to precisely determine the bismuth’s longitudinal and transverse strain sensitivities that are calculated to be equal to +26 and +40.5 respectively. This experimental study is extended to explore the Bi-films’ response to bi-axial strain fields.

B- and P-Doped Si0.8Ge0.2 Thin Film Deposited by Helicon Sputtering for the Micro-Thermoelectric Gas Sensor

2006 ◽  
Vol 320 ◽  
pp. 99-102 ◽  
Author(s):  
Kazuki Tajima ◽  
Woosuck Shin ◽  
Maiko Nishibori ◽  
Norimitsu Murayama ◽  
Toshio Itoh ◽  
...  
Keyword(s):  
Thin Film ◽  
Hydrogen Oxidation ◽  
Exothermic Reaction ◽  
High Sensitivity ◽  
Hydrogen Sensor ◽  
Thermoelectric Effect ◽  
Boron Doped ◽  
Reliable Monitoring ◽  
Ppm Level ◽  
Pt Catalyzed

Micro-thermoelectric hydrogen sensor (micro-THS) with the combination of the thermoelectric effect of Si0.8Ge0.2 thin film and the Pt-catalyzed exothermic reaction of hydrogen oxidation was prepared by microfabrication process. In the viewpoint of high sensitivity of micro-THS, the thermoelectric properties of the Si0.8Ge0.2 thin film could be improved by optimizing carrier concentration using helicon sputtering with an advantage of easy doping control, and sensitivity of the device with this thin film was investigated. As the result, the boron-doped Si0.8Ge0.2 thin film is considered to be the better choice ensuring the reliable monitoring of hydrogen concentration down to ppm level.

Single crystal PZT thin film membrane with highly conductive electrodes

2012 ◽  
Author(s):  
S. Yin ◽  
J. Abergel ◽  
A. Bontempi ◽  
T. Ricart ◽  
G. Le Rhun ◽  
...  
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Pzt Thin Film ◽  
Thin Film Membrane
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