Scientists have discovered a novel material that can emit, detect, and modulate infrared light with high efficiency making it useful for solar and thermal energy harvesting and for optical communication devices. 

Electromagnetic waves are a renewable energy source used for electricity generation, telecommunication, defence and security technologies, sensors, and healthcare services. Scientists use high-tech methods to manipulate such waves precisely -- in dimensions that are thousands of times smaller than the human hair, using specialized materials. However, not all the wavelengths of light (electromagnetic waves) are easy to utilize, especially infrared light, since it is difficult to detect and modulate.

For infrared light applications, intelligent and cutting-edge materials are required which can enable excitation, modulation, and detection at desired spectral range with high efficiencies. Only a few existing materials can serve as hosts for light-matter interactions in the infrared spectral range, albeit with very low efficiencies. The operational spectral range of such materials also does not cover industrially important short wavelength infrared (SWIR) spectral range.

In a significant development, researchers from Bengaluru’s Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), an autonomous institute of Department of Science and Technology (DST) have discovered a novel material called single-crystalline scandium nitride (ScN) that can emit, detect, and modulate infrared light with high efficiencies.

K. C. Maurya and co-workers have utilized a scientific phenomenon called polariton excitations that occur in tailored materials when light couples with either the collective free electron oscillations or polar lattice vibrations to achieve this feat. They have carefully controlled material properties to excite polaritons (a quasi-particle) and achieve strong light-matter interactions in single-crystalline scandium nitride (ScN) using infrared light.

These exotic polaritons in the ScN can be utilized for solar and thermal energy harvesting.  Also, belonging to the same family of materials as gallium nitride (GaN), scandium nitride is compatible with modern complementary-metal-oxide-semiconductor (CMOS) or Si-chip technology and, therefore, could be easily integrated for on-chip optical communication devices.

“From electronics-to-healthcare, defense and security-to-energy technologies, there is a great demand for infrared sources, emitters and sensors. Our work on infrared polaritons in scandium nitride will enable its applications in many such devices,” said Dr. Bivas Saha, Assistant Professor at JNCASR. Apart from JNCASR, researchers from the Centre for Nano Science and Engineering from the Indian Institute of Science (IISc.) and the University of Sydney also participated in this study published recently in the scientific journal Nano Letters. 

Publication:

https://pubs.acs.org/doi/pdf/10.1021/acs.nanolett.2c00912

Contact details: Dr. Bivas Saha email: bsaha@jncasr.ac.in mobile: 63601 26595

Figure: Light manipulation via charge carriers (electric dipole) of material including collective free electron oscillation (plasmon) and lattice oscillation (optical phonon) at the nanoscale dimension.

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