Continuing the recent trend to create and explore ultra thin molecular layers, researchers from the University of Minnesota have created a 20 atom thick film of black phosphorus and demonstrated it can support high speed data communication. The devices were said to have shown a 'vast improvement in efficiency' over comparable parts made from graphene.
According to the team, it is only in the last year that black phosphorus' potential as a semiconductor been realised and added that it can be used to detect light.
"New two-dimensional materials continue to emerge with novel optoelectronic properties," said Professor Mo Li. "Because these materials are two dimensional, it makes perfect sense to place them on chips with flat optical integrated circuits to allow maximal interaction with light and use their novel properties optimally."
The team created optical circuits in silicon and then laid thin flakes of black phosphorus over these structures. This demonstrated that the performance of black phosphorus photodetectors rivals that of comparable devices made of germanium – considered the 'gold standard' in photodetection.
The researchers also sent optical data over fibres at up to 3Gbit/s and recovered it using black phosphorus photodetectors.
Because black phosphorus has a band gap that varies depending on how many layers are stacked together, it can be tuned to absorb light in the visible range but also in the infrared. And, because black phosphorus is a 'direct band' semiconductor, it has the potential to convert electrical signals back into light. This, says the team, could make it a 'one stop solution' for on chip optical communication.
Author
Graham Pitcher
Source: www.newelectronics.co.uk