Developing low-power, high-sensitivity photodetectors for the terahertz (THz) band that operate at room temperature is an important challenge in optoelectronics. In this study, we introduce a photo-thermal-electric (PTE) effect detector based on quasi-free standing bilayer graphene (BLG) on a silicon carbide (SiC) substrate, designed for the THz frequency range. Our detector's performance hinges on a quasi-optical coupling scheme, which integrates an aspherical silicon lens, to optimize impedance matching between the THz antenna and the graphene p-n junction. At room temperature, we achieved a noise equivalent power (NEP) of less than 300 pW/Hz. Through an impedance matching analysis, we coupled a planar antenna with a graphene p-n junction, inserted in parallel to the nano-gap of the antenna, via two coupling capacitors. By adjusting the capacitors and the antenna arm length, we tailored the antenna's maximum infrared power absorption to specific frequencies. The sensitivity, spectral properties, and scalability of our material make it an ideal candidate for future development of far-infrared detectors operating at room temperature.
@article{arxiv.2405.06579,
title = {Terahertz Antenna Impedance Matched to a Graphene Photodetector},
author = {François Joint and Kunyi Zhang and Jayaprakash Poojali and Daniel Lewis and Michael Pedowitz and Brendan Jordan and Gyan Prakash and Ashraf Ali and Kevin Daniels and Rachael L. Myers-Ward and Thomas E. Murphy and Howard D. Drew},
journal= {arXiv preprint arXiv:2405.06579},
year = {2025}
}