New Graphene-based Device Creates Photovoltage In <50 fs
Graphene was produced in small amount for centuries. But, now the demand for graphene has increased and it is widely used in semiconductor, electronics, battery, et al. It has the potential to efficiently convert light into electricity. Earlier studies have demonstrated that graphene-based photothermoelectric devices respond to flashes of light and generate photovoltage in order of picoseconds. However, researchers now know that graphene can convert light into electrical signals at a much higher speed. ICFO researchers in collaboration with scientists from MIT and the University of California (UC), Riverside have recently demonstrated that a new device (graphene-based photodetector) can convert light into electricity in less than 50 femtoseconds (fs) i.e. a twentieth of a millionth of a millionth of a second.
For creating ultrafast photovoltage, the team combined an extremely fast pulse-shaped laser excitation and an electrical readout that is very sensitive in nature. Owing to rapid and efficient interaction between each and every conduction band carriers in graphene, there is a feasibility to create a super-fast photovoltage. This interaction causes an expeditious creation of an electron distribution within the material accompanied by a rise in temperature. The energy from ultrashort flashes of light is taken in and then it is quickly converted into electron heat. Finally, at the interface between two graphene regions that has different doping, the electron heat is converted into a photovoltage. The photo-thermoelectric effect takes place instantly in the device. This ultimately leads to the generation of electrical signals from light in sub-50 fs. The researchers studied the spectral response and found that the spectral responsivity is constant between 500 nm and 1,500 nm.
According to the team, spectral responsivity is consistent with electron heating. Thus, the results of the study make graphene a promising material for femtosecond and broadband photodetector applications. You can have a detailed look at the research paper titled "Generation of photovoltage in graphene on a femtosecond timescale through efficient carrier heating ". It was published in the journal Nature Nanotechnology.
Source: #-Link-Snipped-# | #-Link-Snipped-#
For creating ultrafast photovoltage, the team combined an extremely fast pulse-shaped laser excitation and an electrical readout that is very sensitive in nature. Owing to rapid and efficient interaction between each and every conduction band carriers in graphene, there is a feasibility to create a super-fast photovoltage. This interaction causes an expeditious creation of an electron distribution within the material accompanied by a rise in temperature. The energy from ultrashort flashes of light is taken in and then it is quickly converted into electron heat. Finally, at the interface between two graphene regions that has different doping, the electron heat is converted into a photovoltage. The photo-thermoelectric effect takes place instantly in the device. This ultimately leads to the generation of electrical signals from light in sub-50 fs. The researchers studied the spectral response and found that the spectral responsivity is constant between 500 nm and 1,500 nm.
According to the team, spectral responsivity is consistent with electron heating. Thus, the results of the study make graphene a promising material for femtosecond and broadband photodetector applications. You can have a detailed look at the research paper titled "Generation of photovoltage in graphene on a femtosecond timescale through efficient carrier heating ". It was published in the journal Nature Nanotechnology.
Source: #-Link-Snipped-# | #-Link-Snipped-#
0