A team of researchers from the A*STAR Institute of Materials Research and Engineering (IMRE) has observed that microstructures made up by pairs of touching semiconductor disks yield enhanced terahertz radiation in a tiny V-shaped gap, just a fraction of a micrometre wide. According to the scientists, the effects seen in the microfabricated semiconductor structure could be used in applications such as biosensing and airport security scanners.
Hua Teng and his co-workers developed tiny semiconductor structures made of the chemical elements indium and antimony. From this material, they produced disks of 20µm in diameter, which they arranged such that pairs just touched. The gap between contiguous disks was merely tens to hundreds of nanometers wide. When the researchers exposed the structures to THz radiation, they found that the radiation intensity in the gap was enhanced by more than a hundred times.
The now-verified theoretical predictions came from collaborators at Imperial College London in the UK. "For the present work, IMRE is in charge of the materials growth and the structure fabrication, while Imperial College contributes structure design and characterisation," stated Teng. The A*STAR researchers are now focused on practical applications: they will further explore the unique properties of their semiconductor materials and try to develop devices for THz technology. The group has already succeeded in tuning the THz response of their structure, meaning that they can conveniently adjust the frequency response of their device for different applications.