Terahertz pulse increases electron density 1,000-fold

  • Terahertz pulse increases electron density 1,000-fold

    Researchers at Kyoto University have announced a breakthrough with broad implications for semiconductor-based devices. The findings, announced in the December 20 issue of the journal Nature Communications, may lead to the development of ultra-high-speed transistors and high-efficiency photovoltaic cells.

    Working with standard semiconductor material (gallium arsenide, GaAs), the team observed that exposing the sample to a terahertz (1,000 gigahertz) range electric field pulse caused an avalanche of electron-hole pairs (excitons) to burst forth. This single-cycle pulse, lasting merely a picosecond (10-12 s), resulted in a 1,000-fold increase in exciton density compared with the initial state of the sample.

    "The terahertz pulse exposes the sample to an intense 1 MV/cm2 electric field," explains Hideki Hirori, team leader and Assistant Professor at Kyoto University's Institute for Integrated Cell-Material Sciences (iCeMS). "The resulting exciton avalanche can be confirmed by a bright, near-infrared luminescence, demonstrating a three-order of magnitude increase in the number of carriers."

    Source: physorg.com