2019 Fiscal Year Research-status Report
Study on molybdenum disulfide layer growth on gallium nitride surface for high efficiency UV-visible photodetector
| Project/Area Number |
19K05267
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
カリタ ゴラップ 名古屋工業大学, 工学(系)研究科(研究院), 准教授 (20615629)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | Heterostructure |
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| Outline of Annual Research Achievements |
In this research, we proposed to develop molybdenum disulfide (MoS2) and gallium nitride (GaN) heterostructure for short wavelength (less than 500 nm) photodetector applications. In this prospect, we have studied the van der Waal heteroepitaxial growth of MoS2 film by chemical vapor deposition on the GaN surface. In the initial studies, we have explore growth of MoS2 film on free-standing GaN substrate by sulfurization of molybdenum oxide (MoO3) thin film deposited by thermal evaporation. The study showed that uniform MoS2 layers can be synthesized on a free-standing GaN semiconductor substrate for vertical heterojunction device application. Raman and scanning electron microscopy (SEM) analyses showed homogenous growth of the few-layers MoS2 forming a continuous film, considering the suitability of GaN semiconductor substrate. The fabricated MoS2/GaN vertical heterojunction device showed excellent rectifying diode characteristics with a photovoltaic photoresponsivity under monochromatic light illumination. The X-ray photoelectron spectroscopy (XPS) analysis showed the conduction and valence band offset values are around 0.44 and 2.3 eV with type II band alignment for the MoS2 layer on GaN substrates. This findings can be significant for further development of MoS2/GaN heterostrucutre for developments of efficient short wavelength photodetectors.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In the last one year, we are able to deposit a large-area uniform film of MoS2 on GaN substrate. This showed the merit of proposed research idea and concept to develop highly efficient short wavelength photodetectors. Based on this finding, we are able to smoothly implement the research ideas and further investigation on van der Waal heteroepitaxy of MoS2 layers on GaN in progress. Currently, we are studding the growth of triangular MoS2 crystals on GaN surface and their interface quality by which high quality MoS2/GaN heterostructures can be developed.
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| Strategy for Future Research Activity |
According to the idea of the research proposal, high quality MoS2 layer growth on the GaN surface depending on the nature of surface is greatly emphasized. Further we would like to investigate, the growth behavior of MoS2 layer on gallium and nitrogen terminated GaN, by which we expect to develop a suitable van der Waal heterosturcture. Once the suitable MoS2/GaN heterosturcture is fabricated we are planning to perform the electrical characteristics as well as the wavelength dependent photoresponsitviy and photo transient behavior.
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