High responsivity in MoS2 phototransistors based on charge trapping HfO2 dielectrics

2D Transition Metal Dichalcogenides hold a promising potential in future optoelectronic applications due to their high photoresponsivity and tunable band structure for broadband photodetection. In imaging applications, the detection of weak light signals is crucial for creating a better contrast bet...

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Bibliographic Details
Published in:Communications materials 2020-12, Vol.1 (1), p.1-9, Article 103
Main Authors: Nur, Roda, Tsuchiya, Takashi, Toprasertpong, Kasidit, Terabe, Kazuya, Takagi, Shinichi, Takenaka, Mitsuru
Format: Article
Language:English
Subjects:
639/166/987
639/624/1075/401
Broadband
Chemistry and Materials Science
CMOS
Dielectrics
Hafnium oxide
Image resolution
Light
Materials Science
Molybdenum disulfide
Optoelectronics
Photosensitivity
Phototransistors
Transition metal compounds
Trapping
Two dimensional materials
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Summary:2D Transition Metal Dichalcogenides hold a promising potential in future optoelectronic applications due to their high photoresponsivity and tunable band structure for broadband photodetection. In imaging applications, the detection of weak light signals is crucial for creating a better contrast between bright and dark pixels in order to achieve high resolution images. The photogating effect has been previously shown to offer high light sensitivities; however, the key features required to create this as a dominating photoresponse has yet to be discussed. Here, we report high responsivity and high photogain MoS 2 phototransistors based on the dual function of HfO 2 as a dielectric and charge trapping layer to enhance the photogating effect. As a result, these devices offered a very large responsivity of 1.1 × 10 6  A W −1 , a photogain >10 9 , and a detectivity of 5.6 × 10 13 Jones under low light illumination. This work offers a CMOS compatible process and technique to develop highly photosensitive phototransistors for future low-powered imaging applications. MoS 2 is a promising two-dimensional material for optoelectronics. Here, MoS 2 phototransistors with a dual-functioning HfO 2 dielectric and charge - trapping layer achieve a responsivity of 1.1×10 6 , due to an enhanced photogating effect from band edge alignment with oxygen vacancies.
ISSN:2662-4443
2662-4443
DOI:10.1038/s43246-020-00103-0