Scandium Nitride Film Breaks Thermoelectric Limit: JNCASR, IISc
Why in the news
Scientists at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) and the Indian Institute of Science (IISc), Bengaluru, with the University of Sydney, reported a thermoelectric response in scandium nitride that goes past a long-standing limit for crystalline solids. The work appeared in the journal Science.
Key facts
- The Seebeck coefficient measures the voltage produced by a temperature difference. Crystalline solids normally reach a few hundred microvolts per kelvin, while liquid electrolytes reach millivolts per kelvin.
- The team reported a value beyond -124 mV/K near room temperature (-124.6 mV/K in the PIB summary), around 1,000 times typical semiconductors.
- Material: scandium nitride (ScN), a refractory transition-metal nitride, in thin films of about 200 nm on magnesium oxide substrates, made by ultrahigh-vacuum magnetron sputtering.
- Method: a Heavily Doped, Highly Compensated (HDHC) design, where donors and acceptors offset each other, so charge moves through potential fluctuations as in an electrolyte.
Applications and limits
Possible uses are ultrasensitive temperature sensors, room-temperature single-photon detection and thermal imaging. Scaling up is a challenge because the films need ultrahigh-vacuum growth, and the work is still at laboratory stage.
About the institutes
JNCASR and IISc are both based in Bengaluru; the results were highlighted in PIB’s science coverage of the Ministry of Science and Technology.
Exam angle
- Seebeck effect: temperature difference converts into voltage.
- Scandium nitride is a transition-metal nitride.
- Questions may ask the institutes involved or the application area.