High photoresponsivity and broadband photodetection with a band-engineered WSe2/SnSe2 heterostructure

Hui Xue, Yunyun Dai, Wonjae Kim, Yadong Wang, Xueyin Bai, Mei Qi, Kari Halonen, Harri Lipsanen, Zhipei Sun

    Research output: Contribution to journalArticleScientificpeer-review

    54 Citations (Scopus)


    van der Waals (vdW) heterostructures formed by stacking different two-dimensional layered materials have been demonstrated as a promising platform for next-generation photonic and optoelectronic devices due to their tailorable band-engineering properties. Here, we report a high photoresponsivity and broadband photodetector based on a WSe2/SnSe2 heterostructure. By properly biasing the heterostructure, its band structure changes from near-broken band alignment to type-III band alignment which enables high photoresponsivity from visible to telecommunication wavelengths. The highest photoresponsivity and detectivity at 532 nm are ∼588 A W-1 and 4.4 × 1010 Jones and those at 1550 nm are ∼80 A W-1 and 1.4 × 1010 Jones, which are superior to those of the current state-of-the-art layered transition metal dichalcogenides based photodetectors under similar measurement conditions. Our work not only provides a new method for designing high-performance broadband photodetectors but also enables a deep understanding of the band engineering technology in the vdW heterostructures possible for other applications, such as modulators and lasers.

    Original languageEnglish
    Pages (from-to)3240–3247
    Issue number7
    Publication statusPublished - 21 Feb 2019
    MoE publication typeA1 Journal article-refereed


    We acknowledge funding from the Academy of Finland (Grant No. 276376, 284548, 295777, 304666, 312551, 314810, and 320167), the Academy of Finland Centre of Excellence program (project 312297), the Academy of Finland Flagship program (project 320167), Business Finland (OPEC, A-photonics), the European Union’s Seventh Framework Program (Grant No. 631610), the European Union’s Horizon 2020 research and innovation programme (Grant No. 820423, S2QUIP), Aalto Centre of Quantum Engineering, China Scholarship Council, and the provision of technical facilities of the Micronova, Nanofabrication Centre of Aalto University.


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