Researchers from Kyoto University have discovered a new technique that could dramatically improve the efficiency of some semiconductors. They took gallium arsenide, and blasted it with a terahertz range electric field pulse for just a picosecond, which lead to a 1,000-fold increase in exciton density. An exciton is a pair of an electron and a positively charged area it came from, which are attracted to each other and recombine to luminesce. They're how we get light out of LEDs and other applications, and this new technique could make them dramatically more efficient.
With a three orders of magnitude increase in the conversion of energy to excitons (and an accompanying blast of near-infrared luminescence), the technique's application in solar cells and transistors has already been suggested, but the researchers are looking in other directions. Team leader Prof. Tanaka said:
"Since terahertz waves are sensitive to water, our goal is to create a microscope that will allow us to look inside living cells in real time,. These just-released results using semiconductors are an entirely different field of science, but they demonstrate the rich potential that lies in the study of terahertz waves."