1. High-Performance Graphene Nanowalls/Si Self-Powered Photodetectors with HfO 2 as an Interfacial Layer.
- Author
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Shen, Yuheng, Li, Yulin, Chen, Wencheng, Jiang, Sijie, Li, Cheng, and Cheng, Qijin
- Subjects
PLASMA-enhanced chemical vapor deposition ,HETEROJUNCTIONS ,PHOTODETECTORS ,ATOMIC layer deposition ,GRAPHENE ,QUANTUM wells ,SILICON nitride films - Abstract
Graphene/silicon (Si) heterojunction photodetectors are widely studied in detecting of optical signals from near-infrared to visible light. However, the performance of graphene/Si photodetectors is limited by defects created in the growth process and surface recombination at the interface. Herein, a remote plasma-enhanced chemical vapor deposition is introduced to directly grow graphene nanowalls (GNWs) at a low power of 300 W, which can effectively improve the growth rate and reduce defects. Moreover, hafnium oxide (HfO
2 ) with thicknesses ranging from 1 to 5 nm grown by atomic layer deposition has been employed as an interfacial layer for the GNWs/Si heterojunction photodetector. It is shown that the high-k dielectric layer of HfO2 acts as an electron-blocking and hole transport layer, which minimizes the recombination and reduces the dark current. At an optimized thickness of 3 nm HfO2 , a low dark current of 3.85 × 10−10 , with a responsivity of 0.19 AW−1 , a specific detectivity of 1.38 × 1012 as well as an external quantum efficiency of 47.1% at zero bias, can be obtained for the fabricated GNWs/HfO2 /Si photodetector. This work demonstrates a universal strategy to fabricate high-performance graphene/Si photodetectors. [ABSTRACT FROM AUTHOR]- Published
- 2023
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