In this paper, we present the fabrication of an efficient thin film temperature sensor utilizing chemical vapor deposited carbon nanotube (CNT) film as the sensing element on Si substrates, with diamond-like carbon (DLC):Ni as a catalyst in assisting CNT growth. The fabricated sensor showed good electrical response with change in temperature. Relative linear change in resistance of 18.4% for an increase in temperature from 22 °C to 200 °C was achieved. Various characterizing techniques, such as scanning electron microscopy (SEM) and Raman spectroscopy, were used to characterize the films. In an effort to study device performance, van der Pauw and Hall measurements were carried out to study the dependence of resistance on temperature and magnetic fields. Temperature coefficient of resistance of the sensor was calculated as 1.03 × 10−3/°C. All implications arising from the study are presented. The results establish the aptness of the as-grown CNT film to be used as an active sensing material in thin film temperature sensors.

This study reports a novel approach for growing multilayer thin films consisting of alternate layers of carbon nanotubes (CNT) and nickel on Si (1 0 0) substrates and justifies their use in thin film temperature sensors. A low pressure chemical vapor deposition system was employed for synthesizing CNT films, while Ni films were deposited by electrodeposition. Porous-Si was used as substrate to increase adhesion between the layers of the multilayer structure. The structure of the multilayer films and the quality of the CNT grown were analyzed using several characterization methods, including scanning electron microscopy, x-ray photoelectron spectroscopy, x-ray auger electron spectroscopy and Raman spectroscopy. The electrical characteristics were investigated using a van der Pauw setup and the effect of the increasing number of CNT layers in the multilayer structure was studied. The sensitivity of the multilayer film was found to increase with increasing number of CNT layers, despite the decrease of the temperature coefficient of resistance. On the other hand, the initial resistance was found to increase. Results indicated that these multilayer structures are appropriate for fabricating highly sensitive thin film gauges that can detect lower heat fluxes with more accuracy.

Measurement of transient temperature and heat flux has attained enormous importance with the recent advancement in technology. Certain situations demand transient measurements to be performed for extremely short durations (approximately few seconds) which in turn call for sensors capable of responding within microseconds or even less. Thin-film gauges (TFGs), a particular class of resistance temperature detectors (RTDs), are such kind of sensors which are suitable for above requirements due to their quick and precise measurements in transient environments. The present work aims at designing an in-house fabrication and calibration of fast response TFG prepared by depositing nanocarbon layer on silver films as a laminated composite topping to enhance thermal and electrical properties. A significant improvement in the thermal and electrical conductivity of the composite sensor is observed when compared to gauges made from pure metals.

Combining high sensitivity with fast response and high resolution remains a critical challenge for flexible temperature sensors. The present study leverages the intrinsically high surface-to-volume ratio of nanocomposite fibers as well as the high mechanical properties of nanomaterials for achieving conformable temperature sensors with accurate and fast detection of temperature. To achieve this, nanocomposite films of electrospun polyvinylidene fluoride (PVDF) with embedded silver (Ag) nanoparticles were layered with multiwall carbon nanotubes (MWCNT). The sensor showed a negative temperature coefficient (NTC) with excellent sensitivity of À0.18%/ C and a quick response rate of 11 s. The sensor also exhibited low self-heating errors for an activation current of 1 mA and excellent anti-interference ability when tested for bending forces and wet environments. The nanocomposite fiber-based sensor can be used for real-time monitoring of human body temperature as confirmed by successful experiments. The present work lays the foundation for integrating the sensor further with a user interface to create a wearable temperature monitoring system for mobile healthcare.