Research progress on graphene thermoelectric terahertz detector based on multi-electrode structure

[ China Instrument Network Instrument Development ] Graphene terahertz detectors are limited by the low switching ratio and weak saturation characteristics of materials, and it is difficult to obtain high device response in the terahertz band.

The four-terminal resistance structure device and its bias field induce polarity inversion photocurrent enhancement phenomenon.

Graphene devices based on the principle of thermal electrons have a wide band absorption capacity, and are expected to break through the strict requirements of the device preparation process based on the traditional mixing principle, which is beneficial to large-area device integration.

Supported by the National Key R&D Program, the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences, the State Key Laboratory of Infrared Physics, Lu Wei, Chen Xiaoshuang, Wang Lin, Chen Gang and collaborators avoided the design of traditional devices and adopted a four-terminal resistor structure. Implementing electrode interconnections for different devices (as shown), studies have found that device-switching performance similar to triodes is created by interconnections between electrodes.

At the same time, the researchers generated the asymmetric photocurrent of the graphene channel by the bias effect between the electrodes. Under the bias voltage, the photocurrent of the device showed a linear rising trend, resulting in a photocurrent gain, which was an order of magnitude increase in response to the device. .

In addition, studies have shown that the local field of contact between graphene and metal can drive unbalanced carriers, induce changes in the carrier distribution of graphene channels, and the photoconductive effect of the device under the bias field, the device response can reach 280V/W, the highest value of current international reports.

The research will provide a new way to implement the core components of portable imaging systems and human medical terahertz characterization devices, which was published in the NPG Asia Materials magazine on April 18, 2018.

(Original title: Research progress on graphene thermoelectric terahertz detectors based on multi-electrode structure)