Indian researchers have developed a thin semiconductor layer made by adding magnesium to scandium nitride, opening a new approach to converting heat into electricity. The approximately 200-nanometre-thick layer produced several times higher voltage than expected at room temperature.
The technology is based on the Seebeck effect, in which an electrical voltage is generated between two parts of a metal or semiconductor when one part is heated and the other is kept cooler.
Until now, solid materials have been considered to produce limited amounts of electricity through this effect. Liquid electrolytes or gel-like materials were used to obtain higher output. The new research indicates that a b electrical response can also be achieved from a solid crystal.
The researchers added magnesium to a scandium nitride layer in a highly controlled manner. This changed the distribution of positive and negative charges within the material's internal structure.
Testing showed that the electricity-generating capability increased as the thickness of the layer was reduced. A layer approximately 200 nanometres thick recorded several times higher voltage than expected at room temperature.
The research team also developed an initial light sensor based on the technology. The sensor showed a rapid voltage response when exposed to laser light.
The technology could be used in the future for highly sensitive light sensors, heat detectors and quantum devices. The Indian scientific team has also filed a patent for the discovery.
