Broadband and high responsivity graphene-based photodetectors by engineering atomic-layer-deposition dielectric films*

Ability to covert light of graphene occurs in an ultra-broadband spectral range from violet to mid-infrared region, making graphene as desirable photodetectors for various technology applications in imaging, sensing, spectroscopy and telecommunication. However, the low responsivity of graphene photodetectors about 10 mA/W, due to the ultra-fast recombination of photocarriers, limits their potential applications. Here, we have engineered the interface between graphene and atomic-layer-deposited dielectric films to introduce trapping centrals supporting the highly light reactive of photodetectors. Our graphene-based photodetectors have showed a high sensitivity up to 2 x 10^5 A/W together with a fast response time in a broadband spectral at room temperature.