Efficient photovoltaic effect in graphene/h-BN/silicon heterostructure self-powered photodetector

• Published in: Nano research 2021-06, Vol.14 (6), p.1967-1972
• Main Authors: Won, Ui Yeon, Lee, Boo Heung, Kim, Young Rae, Kang, Won Tae, Lee, Ilmin, Kim, Ji Eun, Lee, Young Hee, Yu, Woo Jong
• Format: Article
• Language: English
• Subjects: Atomic/Molecular Structure and Spectra; Bias; Biomedicine; Biotechnology; Boron; Boron nitride; Carrier transport; Chemistry and Materials Science; Condensed Matter Physics; Dark current; Fabrication; Graphene; Heterostructures; Holes (electron deficiencies); Interfaces; Interlayers; Materials Science; Nanotechnology; Optoelectronic devices; Photoelectric effect; Photoelectric emission; Photometers; Photovoltaic cells; Photovoltaic effect; Photovoltaics; Research Article; Silicon
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-020-2866-x

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 I ph / I dark 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 10 4 times. Also, both I ph / I dark ratio and detectivity, increase by more than 10 4 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.