Toward non-degraded broadband room temperature terahertz detection by graphene plasmon-enhanced photo-thermoelectric effect

In this work, we use T-shaped graphene as the channel of terahertz (THz) detector, and adopt metallic metamaterials near the source. Graphene plasmons at the source side are enhanced by the metallic metamaterials, increasing THz absorption and thus enhancing THz response generated by photo-thermoelectric effect. Because of the non-degraded absorption of graphene plasmons, samples with large metallic metamaterials show non-degraded response within 0.3 THz, and samples with small metallic metamaterials show non-degraded response within 0.75 THz. Series connection instead of parallel connection of each T-shaped graphene channel is expected to yield higher responsivity. Higher responsivity can also be achieved by applying back gate voltage. Samples using graphene with lower mobility show weaker response due to reduced THz absorption, and it is expected that higher response can be obtained by using graphene with higher mobility.