Abstract-HBN-encapsulated, graphene-based room-temperature terahertz receivers with high speed and low noise

Leonardo Viti, David G. Purdie, Antonio Lombardo, Andrea C. Ferrari, Miriam S. Vitiello

https://arxiv.org/abs/2004.10011

Uncooled Terahertz (THz) photodetectors (PDs) showing fast (ps) response and high sensitivity (noise equivalent power (NEP) < nWHz−1/2) over a broad (0.5THz-10THz) frequency range are needed for applications in high-resolution spectroscopy (relative accuracy ~ 
10−11), metrology, quantum information, security, imaging, optical communications. However, present THz receivers cannot provide the required balance between sensitivity, speed, operation temperature and frequency range. Here, we demonstrate an uncooled THz PD combining the low (~2000 kBμm−2) electronic specific heat of high mobility (> 50000 cm2V−1s−1) hBN-encapsulated graphene with the asymmetric field-enhancement produced by a bow-tie antenna resonating at 3 THz. This produces a strong photo-thermoelectric conversion, which simultaneously leads to a combination of high sensitivity (NEP ≤ 160 pWHz−1/2), fast response time (≤3.3ns) and a four orders of magnitude dynamic range, making our devices the fastest, broadband, low noise, room temperature THz PD to date.