Researchers improve light detector

Researchers at the Federal Institute of Technology in Zurich (ETH) have joined forces with colleagues at the National Institute for Material Science in Tsukuba (Japan) to develop an innovative light detector. It consists of two-​dimensional layers of different materials that are said to be promising, according to a statement. 

Graphene is an example of a two-dimensional material, but because it is not the ideal choice for optics applications, the researchers experimented with compounds of transition metals such as molybdenum or tungsten and chalcogenes such as sulphur or tellurium (TMDC). They are highly photosensitive and can be easily combined with silicon optical waveguides, writes the statement. 

“In our detector we wanted to exploit the advantages of different materials whilst overcoming their individual constraints,” explained ETH researcher Nikolaus Flöry. It was a challenge to make the rather slow TMDC-​based detectors faster, but the researchers solved the problem better than expected. “We had hoped to get a few Gigahertz of bandwidth with our new technology – in the end, we actually reached 50 Gigahertz,” said  Flöry. To date, bandwidths of less than a Gigahertz were possible with TMDC-​based detectors.