Novel double slot structure gives rise to the enhanced performance of graphene/silicon hybrid photodetector

(Nanowerk News) The ongoing fourth industrial revolution is data-driven and the optical interconnects are expected to feature higher bandwidth, smaller footprint, and lower power consumption to meet the dramatically growing demand for stronger data processing ability.
As a key element of the optical communication systems, a photodetector can convert the optical signal into the electrical signal and is expected to feature ultrahigh bandwidth.
Graphene/silicon hybrid photodetectors have attracted numerous attentions since its first demonstration due to its potential to realize bandwidth higher than 100 GHz. However, graphene’s atomic-thickness seriously limits its optical absorption thus causing low responsivity.
Plasmonic structures have been explored to enhance the responsivity, but the intrinsic metallic Ohmic absorption of the plasmonic mode limits its performance.
schematic of a double slot graphene photodetector
The schematic of the double slot graphene photodetector. (Image courtesy of the researchers)
To address this issue, the authors of this article (Opto-Electronic Advances, "Graphene photodetector employing double slot structure with enhanced responsivity and large bandwidth") propose a novel double slot structure for high-performance photodetection, taking advantages of both silicon photonics and plasmonics.
With the optimized structural parameters, the double slot structure significantly promotes graphene absorption while maintaining low metallic absorption. Based on the double slot structure, the demonstrated photodetector holds a high responsivity of 603.92 mA/W and a large bandwidth of 78 GHz.
The high-performance photodetector provides a competitive solution for the photodetector on silicon. Moreover, the double slot structure could be beneficial to a broader range of hybrid two-dimensional material/silicon devices to achieve stronger light-matter interaction with lower metallic absorption.
Source: Compuscript
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