Non-thermal plasma assisted CO2 conversion to CO: Influence of non-catalytic glass packing materials

The current research is focused on the decomposition of carbon dioxide (CO2) into carbon monoxide (CO) and oxygen (O2) in a non-thermal plasma reactor using dielectric barrier discharge (DBD) at ambient conditions. Pure CO2 was injected into the DBD reactor at a flow rate of 30 mL min-1, and the voltage was varied between 16 kV to 22 kV. The filamentary micro discharges generated during plasma has a significant effect on CO2 conversion. The effect of packing materials on CO2 conversion was investigated by packing non-catalytic materials such as quartz wool, glass capillary, glass wool, and glass beads in the discharge zone of the DBD reactor. Among the studied packing materials, quartz wool exhibited a maximum CO2 conversion of 9.3 % at a discharge power of 2.0 W and specific energy input (SEI) of 4.0 J mL-1. However, glass capillary exhibited the highest energy efficiency of 1.2 mmol kJ-1 at an SEI of 3.5 J mL-1

Highly Sensitive Electrospun Multiwalled Carbon Nanotubes Embedded Zinc Oxide Nanowire Based Interface for Label Free Biosensing

We demonstrate synthesis of Multiwalled carbon nanotubes (MW CNTs) embedded highly oriented Zinc Oxide (ZnO) nanowires targeted towards development of ultrasen sitive electrochemical nanobiosensors using electrospinning method. The synthesized composite nanowires combines advantages of ZnO such as biocompa tibility, electrostatic affinity towards biomolecules with the excellent conductivity and surface functi onalization capabilities of MWCNTs. Calcinatio n temperature is optimized so as to ensure MWCNTs are present in their original form and at the same time highly crystalline ZnO is obtained. The key advantage o f this process is that there is no separate functionalization pr ocess is required to create functional groups on MWCNTs. Furthermore, the electrochemical activity of MWCNTs embedded ZnO nanowires is much higher as compared to pure ZnO nanowires. We have demonstrated the performance of electrochem ical nanobiosensor using Biotin -streptavidin interaction as model system. The sensor exhibits excellent sensitivity in the range 10 μ gmL -1 - 0.5 fgmL -1 of streptavidin with 0.5fgmL -1 limit of detection

Ultrasensitive, Label Free, Chemiresistive Nanobiosensor Using Multiwalled Carbon Nanotubes Embedded Electrospun SU-8 Nanofibers

This paper reports the synthesis and fabrication of aligned electrospun nanofibers derived out of multiwalled carbon nanotubes (MWCNTs) embedded SU-8 photoresist, which are targeted towards ultrasensitive biosensor applications. The ultrasensitivity (detection in the range of fg/mL) and the specificity of these biosensors were achieved by complementing the inherent advantages of MWCNTs such as high surface to volume ratio and excellent electrical and transduction properties with the ease of surface functionalization of SU-8. The electrospinning process was optimized to precisely align nanofibers in between two electrodes of a copper microelectrode array. MWCNTs not only enhance the conductivity of SU-8 nanofibers but also act as transduction elements. In this paper, MWCNTs were embedded way beyond the percolation threshold and the optimum percentage loading of MWCNTs for maximizing the conductivity of nanofibers was figured out experimentally. As a proof of concept, the detection of myoglobin, an important biomarker for on-set of Acute Myocardial Infection (AMI) has been demonstrated by functionalizing the nanofibers with anti-myoglobin antibodies and carrying out detection using a chemiresistive method. This simple and robust device yielded a detection limit of 6 fg/mL

Hybrid TTSV structure for heat mitigation and energy harvesting in 3D IC

Three Dimensional Integration seems to be one of the best candidates to overcome the various challenges and limitations faced by conventional planer integration. But, thermal issues related to this highly promising integration technique are the main bottleneck for wide scale application. This thermal issue threatens the further progress and development of the 3D IC. The best known possible way to reduce the heat generated within the integrated chip is cooling through the thermal through silicon via (TTSV). This work reports the utilization of time dependent fluctuation of temperature which is generated within the active layers of 3D IC. Pyroelectric effect of TTSV materials is used to convert the heat generated within 3D IC to electrical energy. 60K temperature fluctuation within the IC layer was used to convert as electrical energy and 9.89μW output power was observed. This paper reports the novelty of TTSV structure modification where TTSVs are used as simultaneous energy harvester and heat mitigator

Low temperature, low pressure CMOS compatible Cu -Cu thermo-compression bonding with Ti passivation for 3D IC integration

In this paper, we report the methodology of achieving low temperature, low pressure CMOS compatible Wafer-on-Wafer (WoW) Cu-Cu thermo-compression bonding using optimally chosen ultra-thin layer of Titanium (Ti) as a passivation layer. We systematically studied the effects of Ti thickness on bonding quality via its effects on surface roughness, oxidation prevention and inter diffusion of Cu. Through this study, we have found that a Ti thickness of 3 nm not only results in excellent bonding but also leads to a reduction in operating pressure to 2.5 bar and temperature to 175° C. The reduction in pressure is more than an order of magnitude lower relative to the current state-of-the-art. The lower operating pressure and temperature manifest themselves in a very good homogenous bond further highlighting the efficacy of our approach. Finally, our results have been corroborated by evidence from AFM study of the Cu/Ti surface prior to bonding. The bond strength of Cu-Cu as measured by Instron Microtester measurement system is found to be 190 MPa which compares very well with the reported literatures

Polyaniline Nanofibers as Chemiresistive Transducers: Seeded Synthesis, Characterization and DNA Sensing

In this paper, seeded synthesis of Polyaniline (PANi) nanofibers, their characterization and use as transducers in chemiresistive DNA sensing have been reported. PANi, among many one-dimensional conductive polymers, has shown great potential as a transducer in chemiresistive biosensing in general and DNA sensing in particular, on account of its natural conductivity, ease of doping and surface functionalization. Herein, PANi nanofibers were synthesized using a seeding method, using single walled carbon nanotube (SWCNT) seeds. Surface morphology of the thus synthesized nanofibers were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nanofibers were surface modified with 2% glutaraldehyde for facilitating probe-DNA immobilization, and the results of the same were investigated using Fourier transform infrared spectroscopy. Further, towards analyzing the electrical transport properties of the PANi nanofibers, I-V characteristics were recorded in the applied bias range of -10 V - +10 V, using Agilent B1500A parametric analyzer. As inferred, the I-V response was symmetric about the vertical axis, revealing a crossover between near-Ohmic and power-law dominated regions. As a case study, in this work, the PANi nanofibers were used as transducers for chemiresistive detection of Dengue virus specific consensus primers (DENVCP). © 2020 IEEE

Room temperature desorption of Self Assembled Monolayer from Copper surface for low temperature & low pressure thermocompression bonding

In this paper the utility of Self Assembled Monolayer (SAM) of Propanethiol (C3) for Copper protection from oxidation and subsequent desorption of the Thiol layer from Copper surface by using cold Helium plasma has been investigated. The major bottleneck of achieving low temperature and low pressure bonding is the presence of contamination and oxidation on the Copper surface. Use of Thiol can protect the freshly deposited Copper surface from oxidation and other contamination. Removal of this Thiol layer by Helium plasma just prior to bonding can bring down the required temperature of bonding to 200° and pressure to 4kN. This technique can open up a whole new platform for low temperature bonding for 3D ICs

WoW Post-CMOS compatible Cu-Cu Low temperature, Low pressure thermocompression bonding with Pd passivation Engineering

Surface passivation of Copper plays vital role in accomplishing low temperature, low pressure Wafer-on-Wafer (WoW) Cu-Cu thermocompression bonding, as it not only helps in protecting the Cu surface from oxidation but also smoothen the surface. Ultra-thin Palladium (Pd) layer is regarded as one of the promising passivation layer which can prevent oxidation of copper and in addition it can also minimize the roughness of Cu surface. The thickness of Pd layer plays an important role in achieving good and reliable bonding. In this endeavor, we have optimized the Pd passivation thickness to achieve low temperature (150 ˚C) and low pressure (4 bar) WoW Cu-Cu thermocompression bonding. The optimum thickness of Pd for achieving a good bonding is found out to be 3 nm. Our optimized result yielded an excellent bond interface confirms the reliability of Cu-Cu bonding with Pd passivation

Thermal and Optoelectrical Analysis of La0.7Sr0.3MnO3 Thin Film Thermistor in 8-12 μm Range for Uncooled Microbolometer Application

La0.7Sr0.3MnO3 as a sensing material has shown an amazing potential for uncooled thermal imaging application. Here we report the fabrication of a La0.7Sr0.3MnO3 (LSMO) thin film thermistor on a Si wafer and explored two prime figure-of-merit such as temperature coefficient of resistance (TCR) and optical responsivity, which are very useful parameters to compare the performance with any thermal sensor. The LSMO films were deposited on a SrTiO3(STO) buffer layer with Si/SiO2 as a substrate, by a pulsed laser deposition (PLD) technique. The crystallinity and surface topography of the films were analyzed by X-ray diffraction (XRD) and atomic force microscopy (AFM). The fabricated device was then analyzed for its thermal and electrical characteristics to validate its suitability as an IR sensor. The fabricated device shows very sharp metal-to-insulator (TMI) phase transition temperature at 150 K and very high TCR of +4% K-1 and-4%K-1near 100 K and 200 K respectively, when the temperature was sweeped from 10 K to 300 K. Fabricated Thermistor shows very good thermal response and recovery when subjected to an alternating on-off cycle of IR lamp (150 W) illumination, which confirms its suitability for the highspeed thermal imaging application. The experimental analysis shows highest responsivity of ∼ 21085 V/W at 8.5 μm, which falls in the Long-Wave Infrared (LWIR) region, which is an ideal IR band for any thermal imaging application

Electrochemical Investigation of TLR4/MD-2-Immobilized Polyaniline and Hollow Polyaniline Nanofibers:Toward Real-Time Triaging of Gram-Negative Bacteria Responsible for Delayed Wound Healing

Detecting gram -ve bacterial colonies is crucial in address-ing the clinical challenges associated with chronic wounds and delayed healing. These bacteria can exacerbate wound conditions, hindering natural healing and potentially leading to infections. The electrochemical sensing platform presented in this study serves as a valuable tool for healthcare professionals to make timely and targeted treatment decisions. Toward this, we developed a cost-effective electrochemical sensing platform leveraging the TLR4/MD-2 complex to detect gram -ve bacterial colonies. Our biosensors were meticulously fashioned using polyaniline (PANi) and hollow PANi (HPANi) nanofibers. Notably, the HPANi-based sensors, owing to their distinctive hollow structure, facilitated amplified responses under comparable experimental conditions compared with PANi-based counterparts. The designed sensing platform demonstrated exceptional accuracy in identifying Escherichia coli (gram -ve), showcasing a theoretical detection limit of 0.215 CFU/mL for PANi and a remarkably improved 0.14 CFU/mL for HPANi. These sensors displayed outstanding selectivity for gram -ve bacteria, even amidst gram +ve bacteria and fungi. Moreover, our platform demonstrated remarkable sensitivity, yielding 3.04 ((ΔR/R)/CFU/mL)/cm2 for the HPANi-based sensor, surpassing the performance of the PANi-based sensor at 1.98 ((ΔR/R)/CFU/mL)/cm2.</p