Graphene based heterostructures used for high performance broadband photodetectors

Joint Conference: International Conference on DIAMOND AND CARBON MATERIALS & GRAPHENE AND SEMICONDUCTORS

July 17-18, 2017 Chicago, USA

Shaojuan Li

Soochow University, China

Posters & Accepted Abstracts: J Material Sci Eng

Abstract :

Graphene has recently emerged as a potential candidate to address the shortcomings of traditional IV and III-V semiconductors for fast and broadband photodetectors. Graphene photodetectors can convert light into electrical signal over a broad electromagnetic spectrum from ultraviolet (UV) to terahertz (THz) range. However, the intrinsic optical responsivity of pure graphene-based transistors is usually poor (~10-2 AW-1) due to its relatively low absorption cross-section, fast recombination rate and the absence of gain mechanism. This has led to the formation of heterostructures of graphene with other gain materials that have a band gap, owing to the enhanced device performance in terms of photoresponsivity and photoconductive gain in these hybrid structures. Here, we reported novel photodetectors based on graphene-Bi2Te3, graphene- M0Te2, and graphene-black phosphorus heterostructures and their application for broadband photodetectors. Our results show that the graphene-Bi2Te3 photodetector not only shows greatly enhanced responsivity (up to 35 AW-1 at 532 nm) and an ultra-high photoconductive gain, but also has the capability for broadband photodetection from visible to near-infrared (NIR) wavelengths. We also demonstrated that graphene-M0Te2 hetero structure photodetector achieves a high responsivity of ~970.82 AW-1 (at 1064 nm) and broadband photodetection (visible-1064 nm). Additionally, flexible devices based on the graphene-M0Te2 hetero structure also retains a good photodetection ability after thousands of times bending test (1.2% tensile strain), with a high responsivity of ~60 AW-1 at 1064 nm. Finally, we show that the graphene-black phosphorus heterostructure photodetector shows an ultrahigh responsivity of 3.3Ã?Â?103 AW-1, high photoconductive gain (1.13Ã?Â?109), ultrafast charge transfer (41 fs), polarization dependent photocurrent response, and long term stability at telecommunication band of 1550 nm wavelength. The high performance in NIR range demonstrated in this work paves the way for practical applications in remote sensing, biological imaging and environmental monitoring using 2D materials.

Biography :

Email: sjli@suda.edu.cn