Ultrafast and Broad-Band Graphene Heterojunction Photodetectors with High Gain.
basic_science · Level V
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- Record sourced from PubMed, PMID 38096421.
- Also identified by DOI 10.1021/acsnano.3c07665.
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Abstract
Graphene possesses an exotic band structure that spans a wide range of important technological wavelength regimes for photodetection, all within a single material. Conventional methods aimed at enhancing detection efficiency often suffer from an extended response time when the light is switched off. The task of achieving ultrafast broad-band photodetection with a high gain remains challenging. Here, we propose a devised architecture that combines graphene with a photosensitizer composed of an alternating strip superstructure of WS<sub>2</sub>-WSe<sub>2</sub>. Upon illumination, n<sup>+</sup>-WS<sub>2</sub> and p<sup>+</sup>-WSe<sub>2</sub> strips create alternating electron- and hole-conduction channels in graphene, effectively overcoming the tradeoff between the responsivity and switch time. This configuration allows for achieving a responsivity of 1.7 × 10<sup>7</sup> mA/W, with an extrinsic response time of 3-4 μs. The inclusion of the superstructure booster enables photodetection across a wide range from the near-ultraviolet to mid-infrared regime and offers a distinctive photogating route for high responsivity and fast temporal response in the pursuit of broad-band detection.