Technology has been advancing at an incredible pace over the last 40 years, ever since the invention of integrated circuits. Computers that originally occupied large rooms can now sit on our palm. This rapid growth was due to the invention of an electronic device called the Field Effect Transistor in the year 1947.Semiconductors replaced the bulky vacuum tubes of the day, and reduced the size of electronic circuits. Commercial microprocessors today contain well over 1 billion transistors, and special purpose integrated circuits can contain ten times as many. In 1965 Gordon E Moore, a co-founder of Intel Corporation, predicted that the number of components in a dense integrated circuit would double every two years. Industries use this simple observation, called Moore’s law, to set their targets and drive innovation. This has resulted in faster computing, larger storage, better sensors and more pixels in our cameras. However, we are at a stage where industries find that they cannot shrink transistors further at the same rate, as they reach fundamental physical and economical challenges.
Conventional transistors made of silicon, which measure about 14 nm today, cannot be shrunk much further while ensuring the same performance. While quantum mechanical effects begin to alter transistor behaviour in the nanometre regime, manufacturers have found ways to make these effects negligible. To go below 10 nm, however, manufacturers need formidable economic investment and a move away from Silicon, or to embrace these quantum mechanical effects. Thus, to sustain growth into the future, novel materials and technologies are required, and the field of Nanoscience is essential in this regard. One of the groups working to explore this new frontier is the Low Temperature and Nano-Electronics (LTNE) group at the Indian Institute of Science (IISc) in Bangalore.
The group was established in 2006 by Prof. Arindam Ghosh, currently an Associate Professor at the Department of Physics at IISc. He is a winner of several awards including the Swarnajayanti Fellowship in 2008, awarded by the Government of India and the Shanti Swarup Bhatnagar Prize in 2012, given by the Council of Scientific and Industrial Research (CSIR). These prizes are the most prestigious awards given to scientists in India.
The team has been successful in exploring potential applications for novel nanoscale materials. In a paper recently published in Nature Nanotechnology, the group explores the idea of using a layered Graphene-Molybdenum disulphide structure to detect photons, which are particles of light. While the structure has been previously used for electronic logic and memory devices, the LTNE group was the first to make use of the sensitivity of this material to photons. It appears that they have designed one of the most sensitive Graphene-based photodetectors to date. Such a material could increase the sensitivity of our camera sensors. Prof. Ghosh adds, “Currently, single photon detectors depend on photomultiplier tubes, which cannot be scaled to larger sizes; this could replace them due to their scalability”. The group is also working on thermal sensors, which can be used to make extremely sensitive “thermistors” (resistors sensitive to heat), and on transistors of increased efficiency which could be used in quantum computers.
Nanoscale materials like Graphene have the potential to enhance every aspect of our day-to-day life. They promise faster computers, better cameras and more accurate GPS systems. “We are providing platforms for new technologies like sensors and quantum computers. We are also setting new standards in the measurement of current and resistance” says Prof. Arindam Ghosh about the objectives of the group.
About the Low Temperature and Nano-Electronics group:
The group is headed by Prof. Arindam Ghosh and currently has 20 members. They perform their experiments in two labs, one of them in the Raman building and another in the new Physical sciences building, inside the IISc campus. More information on the group and their work can be found here.