ORCID Profile
0000-0002-6669-5883
Current Organisation
Chungbuk National University
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Publisher: American Chemical Society (ACS)
Date: 25-08-2020
Publisher: Springer Science and Business Media LLC
Date: 24-06-2019
DOI: 10.1038/S41598-019-45204-0
Abstract: Nanophotonic devices manipulating light for high-speed computing are a counterpart of speed-limited electronic circuits. Although plasmonic circuits are a promising platform for subwavelength miniaturization, the logic-operation principle is still limited to mimicking those of photonic waveguides using phase shifts, polarization, interference, and resonance. Meanwhile, reconfigurable interconversion between exciton and plasmon engender emerging applications like exciton transistors and multiplexers, exciton lifiers, chiral valleytronics, and nonlinear excitonics. Here, we propose optical logic principles realized by exciton-plasmon interconversion in Ag-nanowires (NW) overlapped on transition metal dichalcogenides (TMDs) monolayers. Excitons generated from TMDs couple to the Ag-NW plasmons, eventually collected as output signals at the Ag-NW end. Using two lasers, we demonstrate AND gate by modulating single excitons in Ag-NW on MoS 2 and a half-adder by modulating dual excitons in lateral WSe 2 and WS 2 . Moreover, a 4-to-2 binary encoder is realized in partially overlapped MoSe 2 and MoS 2 using four-terminal laser inputs. Our results represent great advances in communication processing for optical photonics integrable with subwavelength architectures.
Publisher: Springer Science and Business Media LLC
Date: 06-07-2018
DOI: 10.1038/S41598-018-28323-Y
Abstract: Layered van der Waals materials have recently attracted attention owing to their exceptional electrical and optical properties in thin layer form. One way to extend their utility is to form a heterostructure which combines various properties of layered materials to reveal intriguing behavior. Conventional heterostructure synthesis methods are difficult to develop and the heterostructure formed can be limited to a small area. Here, we investigate the phase transformation of SnS 2 to SnS by removing sulfur atoms at the top surface using Ar plasma. By varying the plasma power and exposure time, we observed that SnS is subsequently formed on top of the mogul-like structure of SnS 2 . Since SnS is a p- type semiconductor and SnS 2 is an n- type semiconductor, we naturally formed a vertical p-n junction. By using graphene at the top and bottom as transparent electrodes, a vertical p-n diode device is constructed. The device demonstrates good rectifying behavior and large photocurrent generation under white light. This method can be applied to large-area heterostructure synthesis using plasma via phase transformation of various metal dichalcogenides to metal monochalcogenides.
Location: Korea, Republic of
Location: Korea, Republic of
No related grants have been discovered for Hyun Seok LEE.