Scientists develop new infra-red technology for defence and other fields that can outperform silicon devices

Vijay Mohan

Chandigarh, December 24 

Scientists have identified a new method to confine and absorb infrared (IR) light with nanostructures to develop highly efficient infrared absorbers, emitters and modulators that are useful in defence technologies besides other fields like energy, imaging and sensing. 

Researchers at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), have established for the first time infrared light emission and absorption with Gallium Nitride (GaN) nanostructures, according to a statement issued by the Ministry of Science and Technology on Saturday. 

Gallium Nitride (GaN) is a very hard and mechanically stable semiconductor. With higher breakdown strength, faster switching speed, higher thermal conductivity and lower on-resistance, power devices based on GaN significantly outperform silicon-based devices.

It is widely used for blue light emission, and is one of the most advanced semiconductors. Though visible and ultraviolet light applications of GaN have already been realised with commercially available LEDs and laser diodes, utilisation of GaN for IR light harvesting or development of GaN-based IR optical elements is lacking.

“In the last 25 years, blue LED with GaN has changed our world significantly. While the blue light emission from GaN is well-understood, utilising GaN for infrared optics is not well-established. Our work demonstrates a novel pathway for utilising GaN in infrared nanophotonic applications. Importantly, the scientists said that the infrared surface polariton excitations that we have demonstrated can be translated to many other semiconductors as well,” the statement said. 

Scientists at JNCASR used a scientific phenomenon called ‘surface polariton excitations’. Surface polaritons are special modes of electromagnetic waves travelling at the interface of a conductor and an insulator such as air. These alter the morphology and shape of the nanostructures.

To make these GaN nanostructures, the researchers utilised a specialised material deposition instrument called molecular beam epitaxy. It uses ultra-high vacuum, similar to the conditions of outer space, to develop high-quality material nanostructures with dimensions about 1,00,000 times smaller than the width of a human hair.

“This work will greatly benefit in addressing the demand for IR sources and detectors for energy, security, imaging, and other applications,” said Dr Bivas Saha, Assistant Professor, JNCASR.

Such cutting-edge materials allow the creation of polariton-based devices which offer several advantages to electronic devices. Polaritonic technologies have attracted a wide range of applications, such as secure high-speed light-based communication (LiFi), next-generation light sources, solar energy converters, quantum computers and waste-heat converters.