Thermoelectric terahertz photodetectors based on selenium-doped black phosphorus flakes

Abstract

Chemical doping of bulk black phosphorus is a well-recognized way to reduce surface oxidation and degradation. Here, we report on the fabrication of terahertz frequency detectors consisting of an antenna-coupled field-effect transistor (FET) with an active channel of Se-doped black phosphorus. Our devices show a maximum room-temperature hole mobility of 1780 cm2V-1s-1 in a SiO2-encapsulated FET. A room-temperature responsivity of 3 V/W was observed, with a noise-equivalent power of 7 nWHz-1/2 at 3.4 THz, comparable with the state-of-the-art room-temperature photodetectors operating at the same frequency. Therefore, the inclusion of Se dopants in the growth process of black phosphorus crystals enables the optimization of the transport and optical performances of FETs in the far-infrared with a high potential for the development of BP-based electro-optical devices. We also demonstrate that the flake thickness can be tuned according to the target application. Specifically, thicker flakes (>80 nm) are suitable for applications in which high mobility and high speed are essential, thinner flakes (<10 nm) are more appropriate for applications requiring high on/off ratios, while THz photodetection is optimal with flakes 30-40 nm thick, due to the larger carrier density tunability.

arXiv comment8 pages, 4 figures. This is the pre-peer reviewed, authors' version of the Nanoscale article, published in its final form at doi: 10.1039/c8nr09060b

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Cited by in corpus (8)

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• Long-Term Environmental Stability of Nitrogen-Healed Black Phosphorus
• Optimal asymmetry of transistor-based terahertz detectors
• Band gap reconstruction at the interface between black phosphorus and a gold electrode
• On-chip Single-crystal Plasmonic Optoelectronics for Efficient Hot Carrier Collection and Photovoltage Detection
• Unified benchmarking and characterization protocol for nanomaterial-based heterogeneous photodetector technologies