Terahertz photodetection in scalable single-layer-graphene and hexagonal boron nitride heterostructures
Mahdi Asgari, Leonardo Viti, Osman Balcı, Sachin M. Shinde, Jincan Zhang, Hamideh Ramezani, Subash Sharma, Adil Meersha, Guido Menichetti, C. McAleese, Ben R. Conran, X. Wang, Andrea Tomadin, Andrea C. Ferrari, Miriam S. Vitiello
Abstract
The unique optoelectronic properties of single layer graphene (SLG) are ideal for the development of photonic devices across a broad range of frequencies from x rays to microwaves. In the terahertz (THz) frequency range (0.1–10 THz), this has led to the development of optical modulators, nonlinear sources, and photodetectors with state-of-the-art performances. A key challenge is the integration of SLG-based active elements with pre-existing technological platforms in a scalable way, while maintaining performance level unperturbed. Here, we report room temperature THz detectors made of large-area SLG, grown by chemical vapor deposition (CVD) and integrated in antenna-coupled field effect transistors. We selectively activate the photo-thermoelectric detection dynamics, and we employ different dielectric configurations of SLG on Al2O3 with and without large-area CVD hexagonal boron nitride capping to investigate their effect on SLG thermoelectric properties underpinning photodetection. With these scalable architectures, response times ∼5 ns and noise equivalent powers (NEPs) ∼1 nW Hz−1/2 are achieved under zero-bias operation. This shows the feasibility of scalable, large-area, layered material heterostructures for THz detection.