Project's information

Project's title Synthesis and characterization of graphene/TMDCs heterostructures for photodetector
Project’s code GUST.STS.ĐT2020-KHVL01
Research hosting institution Graduate University of Science and Technology
Project leader’s name Nguyen Van Tu
Project duration 01/06/2020 - 31/08/2022
Project’s budget 408 million VND
Classify Fair
Goal and objectives of the project

- Synthesis of large scale, high quality graphene/TMDCs heterostructure
- Investigation of the properties of as-synthesized heterostructures
- Testing application of the heterostructures in photodetector

Main results

- CVD growth of large scale, high crystal graphene/TMDCs (graphene/MoS2, graphene/WS2, graphene/WSe2) were conducted.
- Graphene/MoS2 heterostructure: we try to accomplish high-coverage CVD growth of few-layer MoS2 on graphene by controlling heterogeneous nucleation of MoS2 seeds on graphene by employing a combination of PTAS promoter and a mild ozone treatment of graphene, which result in the CVD growth of few-layer MoS2 flakes with several micrometers in size on graphene.
-  WO3 nanopowders are pre-deposited on the growth substrate and utilized as a W source instead of separate W sources in the CVD system. In this way, mostly mono or bilayer WSe2 flakes, WS2 flakes are grown on the growth substrate with high density and an average size of around 20 µm.
- Graphene/TMDCs (MoS2) heterostructure was succesesfully transferred from the growth substrate to new substrate by wetting chemical method.
- The devices based on graphene/TMDCs (MoS2, WS2) was successfully fabricated by combining photolithograpy and reactive ion etching techniques.
- The electrical and optoelectronic properties of the as-fabricated devices were evaluated.
- The device based on graphene/MoS2 heterostructure reveals negative photoresponse with large responsivity of ~5.2 AW-1 at low operating voltages (VG=0V) and bias voltage of 0.02V under light intensity of 15.6 mWcm-2
- The device based on graphene/MoS2 heterostructure also show negative photoresponse with responsivity ~ 7.6 AW-1 ở Vg = 0V and bias voltage of 0.02V under light intensity of 15.6 mWcm-2

Novelty and actuality and scientific meaningfulness of the results

- Scalable, highly crystalline heterostructure of graphene and 2D-TMDCs (MoS2, WS2, WSe2...) was successfully synthesized by CVD with optimized growth parameters.
- Mechanism of negative photorespone in the heterostructure was proposed. 

Products of the project

Scientific papers in referred journals (list):
- 01 paper published in Journal of Materials Science: Materials in Electronics.
- 01 paper published in Vietnam Journal of Catalysis and Adsorption.
- 01 Poster presentation at the 7th international conference on applied and engineering physic (CAEP-7)
Technological products (describe in details: technical characteristics, place):
- 05 graphene/MoS2 samples with the size of 0.5 cm x 0.5cm stored at Institute of Materials Science.
Other products (if applicable):  Being recruited as a permanent researcher at Institute of Materials Science, VAST according to Decision No.1081/QĐ-KHVL


Post-doctoral project with the code GUST.STS.ĐT2020-KHVL01 has achieved its objectives, all research contents and the related products have been completed as registered. The research team of the project propose Graduate University of Science and Technology to check and take over the project.

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