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Photodetectors Based on 2D Materials
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Photodetectors Based on 2D Materials

Photodetectors are light-sensing devices that transform light into electric current. They are found in a wide range of gadgets in our daily lives. Two-dimensional (2D) graphene has numerous excellent qualities, including being ultra-thin, lightweight, flexible, and easy to construct vertical heterojunctions using van der Waals forces. It is also compatible with traditional microfabrication processes and has programmable energy bands. This makes it a promising candidate for photodetectors to replace conventional materials that do not meet the growing needs of high-frequency communications, national security, new biomedical imaging, and many other fields. Alfa Chemistry can provide unique 2D material solutions that meet customer needs. Please contact us today so we can assist you with your photodetector application research.

Advantages of 2D Materials

Commercially available detectors have a number of drawbacks, including:
(1) low operating temperatures for terahertz and infrared detection.
(2) low operating frequencies.
(3) complex manufacturing processes.

In a novel class of materials utilized for optoelectronic applications, 2D materials have exhibited good characteristics. Interesting aspects include direct properties and a wide variety of band gaps, atomically thin properties, effective light-matter interactions, and heterogeneous structure development.

Photodetector based on MoTe2/graphene heterostructure.Fig 1. Photodetector based on MoTe2/graphene heterostructure. (Yu W, et al. 2017)

Several strategies have been shown to be effective in improving the performance of photodetectors based on two-dimensional materials. Typical strategies include the following.

(1) Device design, including configuration and electrode materials.
(2) Integration with optical structures such as antennas, microcavities, and gratings to enhance the interaction of light with 2D materials.
(3) Integration with strong light-absorbing materials such as QDs or SWCNTs.
(4) Engineering of energy band structures by shearing graphene into quantum dot arrays (GQD) or nanoribbons.
(5) Excitation of plasmon resonance in 2D materials, etc.

Photodetectors Based on Different 2D Materials

Alfa Chemistry is a leader in the field of 2D materials research, and we provide a wide selection of 2D materials and unique services to help you with your photodetector research. The following are some of the 2D materials we can provide that are suitable for photonics applications:

  • Phototransistors and solar cells have benefited from graphene's zero band gap and ultra-high carrier mobility. It is suitable for broadband irradiation detection from UV to terahertz due to its constant absorption over a large range of the electromagnetic spectrum.
  • The peculiar features of monolayer black phosphorus BP ensure its optoelectronic potential. Because the electron-hole pairs are easily generated by absorption of visible and near-infrared light, it is particularly promising for optical detection as a direct bandgap semiconductor with a bandgap that can be controlled from 0.3 eV to 1.9 eV by reducing the number of layers.
  • Tunable bandgaps can be found in TMDCs, ranging from an indirect bandgap of 1.1 eV in bulk crystals to a direct bandgap of 1.9 eV in single crystals. TMDCs can be used to fabricate photodetectors with high on/off ratios.
  • The h-BN is an insulator with a large band gap of 5.97 eV and a graphite-like layer structure that is often employed as a blocking layer to reduce dark currents in heterojunction-based photodetectors. It's also appealing for practical applications because of its chemical stability and strong thermal conductivity.
  • Other van der Waals layered materials in the group III-VI, have also been explored as photoresponsive materials. The UV light sensitivity of the few-layer GaSe is good, with low dark current and high external quantum efficiency. The visible spectrum is almost completely overlapped by the few-layer InSe, which has a narrow indirect band gap.

Model of Si/MoS2 heterostructure based photodetector.Fig 2. Model of Si/MoS2 heterostructure based photodetector. (Kharadi M. A, et al. 2020)

TypeActive MaterialsResponse SpectrumResponsivity
UVFew-layer BP310 nm ~ 400 nm90000 A/W
GQD254 nm2.1 mA/W
GaS254 nm19.2 A/W
WS2 (CVD)365 nm53.3 A/W
Vis-NIRSingle-layer-MoS2400 nm ~ 600 nm880 A/W
Multilayer MoSe2638 nm93.7 A/W
Few-layer ReS2532 nm88600 A/W
MoS2-GaTe21.83 A/W
MoS2/graphene/WSe2400 nm ~ 2400 nm04 A/W (Vis)
MIR-FIRGNR(Passivated by HfO2)10 μm0.18 A/W
Thermal reduced GO3 μm ~ 25 μm9 mA/W
BP400 nm ~ 3750 nm
THzMLG2 THz ~ 3 THz230 A/W
Gra-hBN-Gra0.1 THz ~ 2.5 THz32 A/W
h-BN/few layer BP/h-BN1.7 V/W

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  1. Yu W, et al. (2017). "Near-Infrared Photodetectors Based on MoTe2/Graphene Heterostructure with High Responsivity and Flexibility." Small. 13: 1700268.
  2. Kharadi M. A, et al. (2020). "Silicene/MoS2 Heterojunction for High-Performance Photodetector." IEEE Trans. Electron Devices: 1-6.

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