Diamonds as semiconductors: a cut above the rest

On a trip to Surat in Gujarat, about two years ago, physicist M.S. Ramachandra Rao was impressed by the city's thriving diamond business. "Almost every other household there was engaged in cutting and polishing diamonds. They are masters of the craft; they can cut eight faces in just (a) one-cubic-millimetre piece," says Rao.

However, his interest in diamonds is scientific. For over two decades, Rao, a Professor at the Indian Institute of Technology (IIT) Madras, has been researching the optoelectrical properties of diamonds. In 2023, he started heading the newly launched India Centre for Lab Grown Diamond (InCent-LGD), for which IIT Madras received a grant of ₹242 crore to further research on diamonds.

Diamonds have traditionally been valued for their shine and clarity by jewellers, and for their hardness by industry. The tetrahedral carbon lattice is one of the toughest materials and is popular in wear-resistant coatings in tool bits used for drilling and cutting, reducing the downtime of machines in factories.