Research Breakthroughs

Researchers from the NEMS@CeNSE laboratory have created a highly sensitive graphene-based pressure sensor. It works by measuring changes in resonance frequency when pressure deforms a thin silicon diaphragm. This sensor is much more responsive than traditional silicon sensors, with a record-high performance of 20 kHz/kPa and potential up to 500 kHz/kPa. It can detect very small pressure changes (as low as 90 Pa). The design is simple, adaptable, and could be integrated into modern semiconductor manufacturing, making it highly practical. Read the complete article here at: More, S., & Naik, A. (2024). Graphene resonant pressure sensor with ultrahigh responsivity-range product. Journal of Micromechanics and Microengineering, 34(7), 075006.

Click to read further: https://iopscience.iop.org/article/10.1088/1361-6439/ad5561

Surface-enhanced Raman spectroscopy (SERS) enhances molecular detection on metal surfaces or nanostructures. This study highlights that repeated de-wetting of metal thin films boosts SERS sensitivity over tenfold by creating closely spaced metal nanoclusters that amplify electromagnetic fields. The substrates detect Rhodamine 6G at sub-femtomolar levels and amino acids at micromolar levels. These findings suggest potential for integrating these substrates with nanopores for effective SERS-based sensing at confined, high-concentration conditions. Read the complete article here at: Pal, A., Roshini, R. A., & Varma, M. M. (2024). De-wetted gold nanostructures for SERS-based sensing of static and dynamic targets. Applied Surface Science, 678, 161096.

Click to read further: https://doi.org/10.1016/j.apsusc.2024.161096

This research presents a new method using synchronized optical and electrical measurements to better analyze and improve piezo-MEMS devices. Piezoelectric microelectromechanical systems (MEMS) have great market potential due to their efficient energy conversion. However, energy loss in piezoelectric films can reduce device performance. Current methods to measure energy loss are not ideal for thin-film devices where energy storage and dissipation are spread across layers. The method is demonstrated using specialized MEMS components, enhancing accuracy and performance insights. Read the complete article here: Kumar, V., Tiwari, S., Pillai, G., Pratap, R., & Chandorkar, S. A. (2024). Synchronized Opto-Electro-Mechanical Measurements for Estimation of Energy Dissipation in Thin-Film-Piezoelectric-on-Substrate MEMS/NEMS Devices. Journal of Microelectromechanical Systems.

Click to read further: https://ieeexplore.ieee.org/abstract/document/10705914

Use dual feedback! Then frequency double it to get >100 mW single mode power in visible.

Raman lasers can generate power at any wavelength, but the output spectrum is very broad. Researchers at CeNSE have found that by using the proposed “dual feedback” mechanism, linewidth reduction of ~ 5x is achieved at any wavelength. Frequency doubling this linewidth-reduced near infrared source, >100 mW single mode light of ~ 0.05 nm linewidth in green to yellow is generated.

This paper was published in Optics Express, Vol. 32, No.12, 3 June 2024.

Click to read further: https://opg.optica.org/oe/fulltext.cfm?uri=oe-32-12-20629&id=551029 

In this work, researchers developed an architecture that uses silicon-loaded PZT as the waveguide to realize a modulator to help overcome the electro-optic interaction issue faced in conventional architecture. The device enhanced EO response by 400% is attributed to the improved electro-optic overlap as well as PZT film quality.

The article was published in Applied physics Letters, AIP Publishing, 124, 231105, (2204).

Click to read further: https://pubs.aip.org/aip/apl/article-abstract/124/23/231105/3296495/Silicon-loaded-waveguide-in-sputter-deposited-PZT?redirectedFrom=fulltext

Vanadium Dioxide (VO₂) exhibits a fascinating metal-insulator transition (MIT) used in various applications. However, tailoring its phase transition hysteresis is crucial, for example sensors require minimal hysteresis while memories need a larger value.

In this study, researchers address two problems:

(a) epitaxial integration of VO2 onto Si(100), &

(b) use this as a model system to study the correlation between texture and phase-transition hysteresis in VO2 thin films.

The paper was published in Elsevier, Materialia, Vol. 34, May 2024, 102085. Check out more details on this article at:  https://www.sciencedirect.com/science/article/pii/S2589152924000826?via%3Dihub

Researchers from CeNSE and SSCU, IISc demonstrated that VO2 based neuristors, produced electro-mechanical self-oscillatory behavior akin to biological neurons. High piezoelectric and electrooptic coefficients make it a promising candidate for diverse applications necessitating efficient energy conversion and optical modulation.

The research was published in AIP Publishing, Appl. Phys. Rev. 11, 021410 (2024). Check out more details on this article at:  https://pubs.aip.org/aip/apr/article-abstract/11/2/021410/3283130/Large-electro-opto-mechanical-coupling-in-VO2?redirectedFrom=fulltext

Researchers from the Photonics Research laboratory have developed an innovative silicon embedded grating coupler to improve fibre-chip coupling. The demonstration has far-reaching implications in quantum photonic integrated circuits, on-chip sensors, LiDAR and RADAR applications.

Click to read further: https://doi.org/10.1364/OE.488999