Small is big: Making electronic devices tinier and cheaper

One of the sweet ironies of life is that as human imagination expands, the devices we use are contracting in size. In all likelihood, someone at a laboratory somewhere is already designing a television set that you can carry around your wrist like a watch!

In the modern age of micro-electronics, silicon has been playing an important role in fabricating electronic devices. Its size has been reduced to attain higher computing speeds and lower power consumption. However, silicon loses its attractive properties when its size gets reduced to below 10 nanometres.

The quest for a nanomaterial which exhibits good electronic properties to replace silicon has therefore led to graphene. Excellent features like high mobility at room temperature, high thermal conductivity and negligible resistance for electrons makes graphene an attractive option for designing high-speed electronic device applications. There is a catch, however: the zero band gap of graphene limits its use in electronics and introducing band gap is necessary to make it a promising semiconductor.

Fig. 1 : A tiny phone Credit

What is band gap?

Every solid has its own characteristic energy-band structure. The variation in band structure is responsible for the wide range of electrical characteristics observed in various materials. Substances with large band gaps are generally insulators, those with smaller ones are semiconductors, while conductors either have minuscule band gaps or none.

Fig. 2 : Illustration of band gap in solids

Naresh Alaal, a researcher at the IITB Monash Research Academy, is attempting to introduce a band gap in graphene by combining two dimensional (2D) hybrid structures of graphene and hexagonal boron nitrides (h-BN). By studying the electronic and optical properties of different configurations of graphene and h-BN counterparts, Naresh, under the supervision of Prof. Alok Shukla, Dr. Nikhil Medhekar, hopes to help evolve a version of graphene that has sufficient band gap to ensure that its use in electronics becomes more widespread.

Says Naresh, "On investigating the electronic and optical properties of 1D BNC nanoribbons, we found that zigzag BNC nanoribbons have interesting electronic properties when their edges are terminated with different elements, and exhibit half metallic behaviour without applying an electric field. Studies have shown that half metallic behaviour in 1D (one-dimensional) structures of some materials can be used in spintronics (spin transport electronics) applications. Therefore we are reasonably confident that graphene-based hybrid nanostructures will scale down the size of electronic devices and also the cost of manufacturing."

Fig. 2 : Armchair (left) and zigzag (right) BNC nanoribbons

The IITB-Monash Research Academy is a pioneering joint-venture research partnership between the leading institutions in India and Australia. The Academy, as it is commonly referred to, offers research scholars the opportunity to study for a dually-badged PhD from both IIT Bombay in India and Monash University in Australia. Students spend time at both countries over the course of their research and many of them work on projects that are strongly-interdisciplinary in nature and with an applied research focus.

"A large number of multi-national companies have set up R&D centres in India. It is important that IIT Bombay and Monash University are connected to the research agenda that is being crafted in these R&D Centres. Given its strong industry-facing intent, The Academy is an important vehicle that will help achieve this connection," says Professor Murali Sastry, CEO, IITB-Monash Research Academy.

Naresh, who clearly believes that big things come in small packages, is quick to agree. And is hoping that a cell phone maker some day manufactures a phone that he could slip into his ring finger!

Research scholar: Naresh Alaal, IITB-Monash Research Academy

Project title: Atimistic Simulations of Graphene-Boron nitride Hybrid Nanostructures

Supervisors: Prof. Alok Shukla, Dr. Nikhil Medhekar

Contact details: nareshkdnr@gmail.com

This story was written by Mr Krishna Warrier based on inputs from the research student and IITB-Monash Research Academy. Copyright IITB-Monash Research Academy.