Ui Yeon Won

Abstract: Graphene (Gr)/Si-based optoelectronic devices have attracted a lot of academic attention due to the simpler fabrication processes, low costs, and higher performance of their two-dimensional (2D)/three-dimensional (3D) hybrid interfaces in Schottky junction that promotes electron-hole separation. However, due to the built-in potential of Gr/Si as a photodetector, the Iph /Idark ratio is often hindered near zero-bias at relatively low illumination intensity. This is a major drawback in self-powered photodetectors. In this study, we have demonstrated a self-powered van der Waals heterostructure photodetector in the visible range using a Gr/hexagonal boron nitride (h-BN)/Si structure and clarified that the thin h-BN insertion can engineer asymmetric carrier transport and avoid interlayer coupling at the interface. The dark current was able to be suppressed by inserting an h-BN insulator layer, while maintaining the photocurrent with minimal decrease at near zero-bias. As a result, the normalized photocurrent-to-dark ratio (NPDR) is improved more than 104 times. Also, both Iph/Idark ratio and detectivity, increase by more than 104 times at −0.03 V drain voltage. The proposed Gr/h-BN/Si heterostructure is able to contribute to the introduction of next-generation photodetectors and photovoltaic devices based on graphene or silicon.

TL;DR: This study demonstrates a wide-range vertical photodetector comprising a graphene/h-BN/Au heterostructure in which a h-BN insulating layer is inserted between an Au electrode and graphene photo absorber to generate photocurrents that can overcome the Schottky barrier.

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TL;DR: In this paper, a doping-controlled WSe2-MoSe2 PN heterojunction was proposed to improve the optical properties of the current 2D heterostructures, which can be greatly improved by forming an ideal PN diode via the doping control of 2D materials.