Antenna coupled graphene-FET as ultra-sensitive room temperature broadband THz detector

Rama Murali G K,S S Prabhu,Prathmesh Deshmukh,Palash Kumar Basu

doi:10.1063/1.5063399

Abstract

A high sensitivity, low power (∼1μW to 10 μW), room temperature, antenna coupled, THz (0.8 THz) detector is presented by means field effect transistor (FETs) fabricated on epitaxial-grown graphene on silicon carbide. The contact resistance across the source and drain are made high to study the effect of THz response. It is demonstrated that the energy coupled to the antenna is the important parameter in designing the ultra-sensitive THz detectors rather than the contact resistances and channel conductivity. The realised graphene based detectors shows quite good responsivity (&gt;535 V/W) and noise equivalent power (NEP) (&lt;100pW/Hz0.5). The individual contributions of photo voltage due to plasma wave generation (PWG) and photo thermo-electric effect (PTE) in the effective THz detection is estimated. It is also seen that the temperature of the hot carriers generated in the FET channel due to PTE is varying with the gate bias and not constant as assumed in earlier works. A new method is proposed in this work for calculating the antenna coupling factor which varies with incident THz-radiation power. A comprehensive analytical model is worked out to understand the graphene based detector performance.

Highlights

In the pioneer work by Dykanov and Shur,[1] plasma wave generation of electrons in 2DEG is modeled with hydrodynamic equations to develop FETs as quadratic detectors of THz radiation.[2]
With the properties of linear dispersion relation, high Fermi velocity (106 ms-15), large carrier mobility and very high current saturation (106-107 cms-17), graphene FET becomes a potential candidate for THz detector
Vicarelli et al,[9] demonstrates first room-temperature terahertz detectors based on antenna-coupled top gated graphene FET operating at 0.3THz

Summary

Introduction

In the pioneer work by Dykanov and Shur,[1] plasma wave generation of electrons in 2DEG is modeled with hydrodynamic equations to develop FETs as quadratic detectors of THz radiation.[2]. Antenna coupled graphene-FET as ultra-sensitive room temperature broadband THz detector

Results

Conclusion