ABSTRACT
In this paper, the piezoresistive sensitivity is enhanced by applying uniform mechanical stress (MS) on the multi-nanosheet (NS) channels of sub-5 nm junctionless field-effect transistors. The piezoresistivity of the sensing device is boosted by narrowing channel conductivity using low gate biasing and reducing physical channel width, resulting in the maximum (â¼6 times higher) sensitivity observed in the subthreshold regime compared to the ON-state condition. In addition, the sensitivity is extensively increased by â¼30.3% near the threshold voltage with horizontally multi-NS stacking due to the uniform MS distribution on the multi-NS channels, which can sense slight deflection of pressure on the circular diaphragm. These results show that the tunable sensitivity of junctionless multi-channel devices is superior to the inversion mode, a consequence of the less scattering effect, better thermal stability, and low electronic noise.
ABSTRACT
Wearable electronics and smart harvesting textile studies require a material system that resists physical stimulation. Such applications require receptive piezo-polymers, and their activation-free preparation that can translate into a continuous large-area film. In this work, it is discussed whether the ß-content of piezo-polymer is extended with no use of any activation (i.e. poling), and if the ß-content increases, it can be processed over a wide range of surfaces like large-area piezo-film. Such prerequisites within polyvinylidene fluoride-molybdenum disulfide ((PVDF)-MoS2 ) piezo-polymer are thoroughly experimented here to develop a high-performance piezo-film. A MoS2 -mediated PVDF piezo-polymer (termed as P+ -MoS2 ) is introduced, in which no extra ß-enhancement activation step is required after spin coating. Experimental results record ß â§ 80% which allows to harvest the voltage and current in the level of ≈17 V and 1 µA, respectively which satisfies 5 V supply voltage requirement of the current microelectronics, and internet of things (IoT). In addition, the capacitors having different capacities are charged using the developed nanogenerator to check its practical applicability. Therefore, the transition process of P-MoS2 to aligned P+ -MoS2 due to passive interlocking (PiL) through rotating directional field is novel and found to be a principal reason for ß-enhancement in fabricated devices.
Subject(s)
Electronics , Molybdenum , Fluorocarbon Polymers , PolymersABSTRACT
In this article, a comprehensive analysis of the impact of electrothermal characteristics in the junctionless silicon-nanotube (Si-NT) field-effect-transistors is carried out using the Sentaurus TCAD. The combined study of the variation in thermal contact resistance (1 × 10-9to 1 × 10-8m2W K-1), ambient temperature (300-400 K), and spacer length (5-20 nm) are performed. Significant improvements are observed in carrier temperature by 14%, lattice temperature by 13.7%, and gate leakage current from 0.787 nA to 0.218 fA due to the change in the spacer length. Further, a change in the drain current of 25.6% for thermal resistance (Rth) and of 11.62% due to ambient temperature is observed. We also show that the junctionless device suffers significantly less from self-heating effects because of the electric field intensity, which is much lower in the channel region.
ABSTRACT
The present study investigates the piezoresistive properties of polycrystalline MoS2 film for strain-sensing applications. The gauge factor (GF) of the flexible MoS2 device (MoS2/PET) has been calculated to be 102 ± 5 in the stress range from ~7 MPa to ~14 MPa. In addition, to improve the sensing stress range, the flexible strain sensors are encapsulated by SU-8. The effect of encapsulation layer thickness is reflected in the GF, which is attributed to the shifting of the neutral axis. However, the calculated GF is constant in the higher stress range, 80 ± 2 and 12 ± 1 for 2 µm and 10 µm thick SU-8, respectively. Herein, we report a cost-effective and scalable approach to fabricate large-area polycrystalline MoS2-based flexible sensors for a wider stress range. The encapsulated devices remained undistorted and intact for stress values beyond 14 MPa. Further, we demonstrate the durability of the fabricated sensors with body movements, such as hand gestures, for all the three types of strain sensor.
ABSTRACT
An all metal based electrostatic nanoelectromechanical switch has been fabricated using a one mask process. High temperature cycling behavior is demonstrated in a vacuum chamber at 300 °C for more than 28 hours. The compelling results indicate that the design is promising for the realization of rugged electronics with three-dimensional integration.
ABSTRACT
Monitoring blood flow rate inside prosthetic vascular grafts enables an early detection of the graft degradation, followed by the timely intervention and prevention of the graft failure. This paper presents an inductively powered implantable blood flow sensor microsystem with bidirectional telemetry. The microsystem integrates silicon nanowire (SiNW) sensors with tunable piezoresistivity, an ultralow-power application-specific integrated circuit (ASIC), and two miniature coils that are coupled with a larger coil in an external monitoring unit to form a passive wireless link. Operating at 13.56-MHz carrier frequency, the implantable microsystem receives power and command from the external unit and backscatters digitized sensor readout through the coupling coils. The ASIC fabricated in 0.18-µm CMOS process occupies an active area of 1.5 × 1.78 mm (2) and consumes 21.6 µW only. The sensors based on the SiNW and diaphragm structure provide a gauge factor higher than 300 when a small negative tuning voltage (-0.5-0 V) is applied. The measured performance of the pressure sensor and ASIC has demonstrated 0.176 mmHg/âHz sensing resolution.
