Room Temperature Graphene Mid-Infrared Bolometer with a Broad Operational Wavelength Range
Shaofan Yuan, Renwen Yu, Chao Ma, Bingchen Deng, Qiushi Guo, Xiaolong Chen, Cheng Li, Chen Chen, Kenji Watanabe, Takashi Taniguchi, F. Javier Garcı́a de Abajo, Fengnian Xia
Abstract
The past decade has witnessed the realization of numerous different types of graphene photodetectors with a strong focus on the visible and near-infrared spectral range, in which various high-performance photodetectors exist based on traditional materials such as silicon and III–V compound semiconductors. However, high-speed mid-infrared photodetection at room temperature is still an unsolved challenge, despite its importance in applications such as security, sensing, and imaging. Here we address this challenge by demonstrating that high-quality graphene is an ideal high-speed bolometric material for the less-explored yet critical mid-infrared photodetection at room temperature, due to its broadband absorption, small heat capacity, and remarkably large temperature coefficient of resistance (TCR) of up to around 1% per Kelvin, which is comparable to that of commercial bolometric materials. We demonstrate a device based on graphene encapsulated in hexagonal boron nitride (hBN) exhibiting decent extrinsic responsivities of 5.1–1.4 mA/W in the 3.4–12 μm wavelength range at room temperature, and further predict a detection bandwidth of at least 47 MHz. Our demonstration lays the foundations for graphene high-speed mid-infrared technologies.