The Vienna University of Technology’s (TU Vienna) scientists have designed light-detectors manufactured from graphene and studied their special properties. They showed how graphene is capable of converting light into electrical signals at a very rapid speed.
Graphene Light makes the electrons flow
When data transmission takes place using light pulses as in fiber optic cables, the light is changed into electrical signals, which can then be processed using a computer. This conversion happens due to the photoelectric effect. With light stimulation, it is possible to move electrons from their respective positions that result in the generation of an electrical current.
Last year, the scientists had proved that graphene can convert light into electronic signals at fast rate, but the reaction time of graphene could not be calculated. Since It was impossible to measure the photoelectric effect in graphene using normal techniques, the graphene detector was subjected to laser pulses continually. This technique allowed the measurement of the resulting photo-current. The maximum frequency of the detector can be measured by varying the delay time between the laser pulses. Using this method, the graphene photo-detectors can be used to transfer data at the rate of 30 GB/s or above. The result clearly proves the astonishing ability of graphene and its use for optoelectronic applications.
Graphene-photodetectors can function at high frequencies owing to the short lifetime of graphene’s charge carriers. The electrons move their initial fixed position and get fixed at another permanent position after a few picoseconds, thus resulting in an electrical current. Following this, the graphene photodetector is subjected to another light signal which releases electrons, thus producing the next electrical signal.
Source: http://www.tuwien.ac.at/