Abstract-Dual origin of room temperature sub-terahertz photoresponse in graphene field effect transistors

D. A. Bandurin,  I. Gayduchenko, Y. Cao,  M. Moskotin, A. Principi,  I. V. Grigorieva, G. Goltsman, G. Fedorov, D. Svintsov,

https://aip.scitation.org/doi/abs/10.1063/1.5018151

Graphene is considered as a promising platform for detectors of high-frequency radiation up to the terahertz (THz) range due to its superior electron mobility. Previously, it has been shown that graphene field effect transistors (FETs) exhibit room temperature broadband photoresponse to incoming THz radiation, thanks to the thermoelectric and/or plasma wave rectification. Both effects exhibit similar functional dependences on the gate voltage, and therefore, it was difficult to disentangle these contributions in previous studies. In this letter, we report on combined experimental and theoretical studies of sub-THz response in graphene field-effect transistors analyzed at different temperatures. This temperature-dependent study allowed us to reveal the role of the photo-thermoelectric effect, p-n junction rectification, and plasmonic rectification in the sub-THz photoresponse of graphene FETs.

Abstract-Infrared Properties and Terahertz Wave Modulation of Graphene/MnZn Ferrite/p-Si Heterojunctions

Dainan Zhang, Miaoqing Wei, Tianlong Wen, Yulong Liao, Lichuan JinJie Li, Qiye Wen

https://link.springer.com/article/10.1186%2Fs11671-017-2250-2

MnZn ferrite thin films were deposited on p-Si substrate and used as the dielectric layer in the graphene field effect transistor for infrared and terahertz device applications. The conditions for MnZn ferrite thin film deposition were optimized before device fabrication. The infrared properties and terahertz wave modulation were studied at different gate voltage. The resistive and magnetic MnZn ferrite thin films are highly transparent for THz wave, which make it possible to magnetically modulate the transmitted THz wave via the large magnetoresistance of graphene monolayer.

Abstract-Highly Sensitive and Wide-Band Tunable Terahertz Response of Plasma Waves Based on Graphene Field Effect Transistors

• Lin Wang,
• Xiaoshuang Chen,
• Anqi Yu,
• Yang Zhang,
• Jiayi Ding
• & Wei Lu

• Affiliations
• Contributions
• Corresponding author

http://www.nature.com/srep/2014/140627/srep05470/full/srep05470.html

Scientific Reports

 

4,

 

Article number:

 

5470

 

doi:10.1038/srep05470

Received

 

30 January 2014 

Accepted

 

27 May 2014 

Published

 

27 June 2014

Terahertz (THz) technology is becoming a spotlight of scientific interest due to its promising myriad applications including imaging, spectroscopy, industry control and communication. However, one of the major bottlenecks for advancing this field is due to lack of well-developed solid-state sources and detectors operating at THz gap which serves to mark the boundary between electronics and photonics. Here, we demonstrate exceptionally wide tunable terahertz plasma-wave excitation can be realized in the channel of micrometer-level graphene field effect transistors (FET). Owing to the intrinsic high propagation velocity of plasma waves (>~10⁸ cm/s) and Dirac band structure, the plasma-wave graphene-FETs yield promising prospects for fast sensing, THz detection, etc. The results indicate that the multiple guide-wave resonances in the graphene sheets can lead to the deep sub-wavelength confinement of terahertz wave and with Q-factor orders of magnitude higher than that of conventional 2DEG system at room temperature. Rooted in this understanding, the performance trade-off among signal attenuation, broadband operation, on-chip integrability can be avoided in future THz smart photonic network system by merging photonics and electronics. The unique properties presented can open up the exciting routes to compact solid state tunable THz detectors, filters, and wide band subwavelength imaging based on the graphene-FETs.