Silicon Updates: Graphene helps Creating Flexible Electronics in Terahertz EM radiations

Electronics, till date, deal only with the frequency ranges of gigahertz. Most significantly, the radiations of gigahertz range are used in communication devices – cellular phones, Wi-Fi signals etc. But five years ago, scientists have devised photodetectors capable of detecting the frequencies of visible and near-infrared ranges. With the combination of Graphene and quantum dots, the scientists were able to create flexible photodetectors. However, these photodetectors are not capable of working in the terahertz frequency range.

Applications of Terahertz photodetectors:

Gigahertz radiations are normally blocked by certain materials. The major advantage of terahertz radiation over gigahertz radiation is that they “penetrate” through the materials, which can block the gigahertz radiation to pass through them.  With the recent researches, scientists have created the photodetectors capable of working in the terahertz range. The immediate application of these photodetectors of terahertz range can be found in medical diagnostics and intelligent vehicles.

Applications of Terahertz Graphene photodetector

Getting into details, a team of researchers at from Chalmers University, Sweden has been working on the graphene materials to create flexible photodetectors, that operate and sustain in the terahertz range and they have succeeded! This team of researchers has recently published a journal in Applied Physics Letter.

Graphene photodetector

Transistor structure:

Field Effect Transistors (FETs) are normally built either up on a p-type or n-type substrate and a complementary channel region. The journal published by the research team is about the FET built up on a plastic substrate, with a graphene material forming the channel. The team claims that this is the base of achieving the detection of 330 – 500 GHz ranges of frequencies.

Structure of Graphene Field Effect Transistor (FET)

Terahertz graphene-based FET detectors have been demonstrated on rigid substrates such as SiO2/Silicon. And flexible devices (graphene and other concepts) have been demonstrated at RF/microwave frequencies. -  Jan Stake, head of the Terahertz and Millimetre Wave Laboratory at Chalmers.

This research makes it possible to create an environment of Internet of Things via high-bandwidth 5G technologies. Apparently, this is the transition phase of electronics from gigahertz (10⁹ Hz) range to terahertz (10¹² Hz) range.