Research

ELECTRONICS

For the student and the industry
Electronic devices power the modern world. Peer inside any modern contraption and you will find integrated circuits, sensors, displays, energy harvesters and light sources.

The climate crisis has precipitated a need to re-evaluate our energy infrastructure. To replace fossil fuels with renewable energy, we are developing next-generation perovskite solar cells that are cheaper, more scalable, and more functional. Prof. Sushobhan Avasthi and Prof. Aditya Sadhanala are developing equipment to fabricate perovskite cells are scale. In fact, they are one of the few groups in India that can print perovskite solar cells on A4-sized sheets. They are also tackling more fundamental issues of efficiency, stability, and lead-toxicity. Prof. Sushobhan develops advanced electrical characterizations techniques to characterize defects in devices. He is also working with chemists to develop 2D/3D perovskites with improved stability. Prof. Aditya builds advanced optoelectronics characterization equipment, like photothermal deflection spectroscopy. Prof. Aditya is investigating nanopatterned back-contact architecture for high-efficiency lead-free perovskite solar cells. He is also fabricating light-emitting diodes using small-molecules and nanocrystals.

As the energy infrastructure electrifies, we need efficient and cost-effective devices to convert AC to DC power and to step-up/step-down voltages. Gallium nitride (GaN) and Gallium oxide (GaO) devices underpin this revolution. The use of GaN for LED lights is well-known. Prof. Digbijoy Nath, Prof. S Raghavan and Prof. Navakanta Bhat, in collaboration with other faculty members at the Institute, design and fabricate GaN power transistors on indigenously developed material platform which can carry several Amps of current and block several hundred volts of potential! Such devices will reduce the size of your laptop and phone chargers to a point where it disappears into the plug. Prof. Digbijoy is also working on GaO power devices that can withstand kilovolt and are promising for next-generation power switches! GaN transistors are also very attractive for microwave an RF electronics for the upcoming 5G/6G revolution as well as for radar applications and satellite communications. Leveraging the nanolithography, Prof. Digbijoy’s group fabricates cm-scaled devices with critical features that are just a few tens of nanometers whose cut-off frequencies can go above 200 GHz. The precise control allows very fast movement of electrons, enabling amplifiers which can provide unprecedented output power at several GHz.

Faster-speeds and energy-efficiency are also the need for next-generation computation and memory devices. To support emerging technologies like artificial intelligence (AI), machine learning (ML) and internet-of-things (IoT), we must go beyond Moore’s law to “more-than-Moore” paradigm. Here devices don’t just have silicon but also new materials with novel functionality. Prof. Chandan Kumar conducts fundamental transport studies in graphene and transition metal dichalcogenide (TMDCs). The group stacks layered compounds on top of each other to unlock novel electronic properties. Prof. Navakanta Bhat focusses on processing and device innovations to demonstrate ultra-low power and highly scaled 2D FETs. Prof. Sushobhan is attempting to integrated ferroelectrics with silicon to demonstrate new class of non-volatile memories. Prof. Sreetosh Goswami is working with novel organic molecules and inorganic materials to demonstrate devices for analog computing, spiking neutral network, and reconfigurable computers.

As our infrastructure becomes “smarter”, sensors become ubiquitous. Advances in healthcare, city management, process control, are automotive are often underwritten by new transductions. Prof. Navakanta Bhat has designed and commercialized a range of bio-sensors, gas-sensors, and pressure sensors. To monitor air pollution and health, he has developed and deployed a range of reliable and low-cost sensors to track gases like O2, CO, H2, NO2, H2S, N2H4, etc. He has developed electrochemical bio-sensors for important point of care diagnostics, with particular attention to Diabetes. In collaboration, Prof. Navakanta has also developed a series of pressure sensors for diverse applications like intercranial surgery, light-combat helicopter, and nuclear reactors. Prof. Sushobhan is designing low-cost infrared detectors that work in the strategic band of short-wave IR (SWIR) and mid-wave IR (MWIR). Existing technology is export-controlled and awfully expensive. Prof. Sushobhan is working with chemists to fabricate IR photodetectors using nanocrystals. The technology will be 100x cheaper and have application is night-vision, safety, process control, and surveillance.

Light-matter interaction is key to optical sensing. Conventional optical sensors use bulk and free-space optics, which works spectacularly well in laboratory and tabletop setups. Optical sensors are intrinsically selective, unlike electrochemical and other probing methods. However, the sensitivity of optical sensors primarily depends on the light-matter interaction. The focusing ability of the system constrains the volume of integration in conventional free-space lens-based optics. At the photonic research laboratory led by professor Shankar Kumar Selvaraja, photonic integrated circuits increase light-matter integration using waveguides and optical cavities. Compared to state-of-the-art bulk systems, one could achieve a 3-order improvement in Raman spectroscopy. The circuits could be used to perform trace-gas sensing as well. The circuits can operate at a wide range of wavelengths, from ultraviolet to mid-infrared.