High Responsivity and Quantum Efficiency of Graphene/Silicon Photodiodes Achieved by Interdigitating Schottky and Gated Regions

Abstract

Graphene / silicon (G/Si) heterostructures have been studied extensively in the past years for applications such as photodiodes, photodetectors and solar cells, with a growing focus on efficiency and performance. Here, a specific contact pattern scheme with interdigitated Schottky and graphene/insulator/silicon (GIS) structures is explored to experimentally demonstrate highly sensitive G/Si photodiodes. With the proposed design, an external quantum efficiency (EQE) of > 80% is achieved for wavelengths ranging from 380 to 930 nm.A maximum EQE of 98% is observed at 850 nm, where the responsivity peaks to 635 mA/W, surpassing conventional Si p-n photodiodes. This efficiency is attributed to the highly effective collection of charge carriers photogenerated in Si under the GIS parts of the diodes.The experimental data is supported by numerical simulations of the diodes. Based on these results, a definition for the 'true' active area in G/Si photodiodes is proposed, which may serve towards standardization of G/Si based optoelectronic devices.

Electron Transport across Vertical Silicon/MoS2/Graphene Heterostructures: Towards Efficient Emitter Diodes for Graphene Base Hot Electron Transistors

“…S4, in supporting information). A comparison of the room temperature I-V characteristics of the present devices with the results from "graphene/n-Si" Schottky diodes intensively studied by our research group[39][40][41] clearly indicates the electrical impact of MoS2 in the present structures.…”

Ultrasensitive and fast photoresponse in graphene/silicon-on-insulator hybrid structure by manipulating the photogating effect

“…Graphene behaves as a fast transfer channel of photogenerated charge herein. In MPE mechanism, when a vertical voltage is applied, the accumulation of induced charge on the two sides of silicon oxide will be manipulated, which will change the carrier concentration in the top-silicon [31]. The excess electrons or holes will inject into graphene, resulting in a change of sheet current.…”

Camphor-Based CVD Bilayer Graphene/Si Heterostructures for Self-Powered and Broadband Photodetection

“…Note that the responsivity obtained here is competitive with that obtained from the conventional CVD graphene/Si Schottky PDs (0.51 A/W at 532 nm) [ 49 ] and much higher than that obtained from the pristine graphene PDs (1 × 10 −3 A/W) [ 47 ], graphene oxide/Si Schottky PDs (~63 mA/W at 445 nm), [ 50 ] and graphene/insulator/Si (GIS) PDs (~20 mA/W at 1200 nm) [ 8 ]. Furthermore, the detectivity ( D* ) is an important parameter used to analyze the PD performance [ 51 , 52 ].…”

“…Until now, Si-based PDs with different structures (e.g., Schottky photodiodes, p-n photodiodes, metal-semiconductor-metal (MSM) photodiodes, phototransistors, and p-i-n photodiodes) have been intensively studied and developed [ 4 , 5 , 6 ]. Among them, Si Schottky photodiodes provide superior radiation resistance and high-speed operation and can be easily integrated with photoelectronic and microelectromechanical systems for photon detection [ 7 , 8 ]. Furthermore, the self-powered operation mode (at zero bias) of Schottky photodiodes could provide many benefits for intelligent sensors working in 5th generation wireless systems [ 9 , 10 ].…”