Molybdenum Disulphide Transistors Direct Tailoring After-Fabrication

Making electronic devices from exfoliated 2-D materials can be tricky. The Daniel Granados team of IMDEA Nanociencia designed a solution that includes post-fabrication customization of MOS 2-FET transistors using pulsed focused electron beam-induced etching.

Transition metal disulfides are thin layers of 2-D atoms bound together by Van der Waals force. These materials exhibit thickness-dependent variations in their physical properties and can be used in different optoelectronic applications.

Atomic thin layers of MoS2 can be separated by micromechanical stripping, but manufacturing optoelectronic devices from mechanically stripped MoS2 is a complex process. Even with the deterministic stamping method, the geometry of the device is limited by the flake shape in all cases. Even when CVD (Chemical Vapor Deposition) technology is used, device fabrication is hindered by materials growing in the island, which have reduced size and different physical properties.

Therefore, it is very interesting to develop the technology of customizing device geometry after the manufacturing step is completed. The group of Prof. Daniel Granados at IMDEA Nanociencia proposed an intelligent solution by modifying the geometry of several field-effect transistors (FET) made of exfoliated MoS2. The proposed method uses focused electron beam induced etching (FEBIE) and pulsed electron beam variation. The beam uses a pattern generator to scan the surface into a designed geometry, modify the conduction channel between the source and drain of the transistor, and allow customized device performance.

Compared with the method using multiple manufacturing steps, this method has several advantages. First, it combines patterning and etching in one step rather than two-step nanofabrication. Secondly, it allows electronic and optical characterization before and after customization steps in a simple scheme. Lastly, pulsed FEBIE is a chemical method whose electron beam energy is lower than that of other studies (2.5 kV), which can reduce sample damage and prevent the distortion of MoS2 lattice. Because of these advantages, Granados et al. proposed nanoscissors. It is a significant alternative to expensive and time-consuming nanofabrication technologies, and has great potential for customization of post-fabrication with electrical and geometric characteristics of electronic and photoelectric devices.Making electronic devices from exfoliated 2-D materials can be tricky. The Daniel Granados team of IMDEA Nanociencia designed a solution that includes post-fabrication customization of MOS 2-FET transistors using pulsed focused electron beam-induced etching.

Transition metal disulfides are thin layers of 2-D atoms bound together by Van der Waals force. These materials exhibit thickness-dependent variations in their physical properties and can be used in different optoelectronic applications.

Atomic thin layers of MoS2 can be separated by micromechanical stripping, but manufacturing optoelectronic devices from mechanically stripped MoS2 is a complex process. Even with the deterministic stamping method, the geometry of the device is limited by the flake shape in all cases. Even when CVD (Chemical Vapor Deposition) technology is used, device fabrication is hindered by materials growing in the island, which have reduced size and different physical properties.

Therefore, it is very interesting to develop the technology of customizing device geometry after the manufacturing step is completed. The group of Prof. Daniel Granados at IMDEA Nanociencia proposed an intelligent solution by modifying the geometry of several field-effect transistors (FET) made of exfoliated MoS2. The proposed method uses focused electron beam induced etching (FEBIE) and pulsed electron beam variation. The beam uses a pattern generator to scan the surface into a designed geometry, modify the conduction channel between the source and drain of the transistor, and allow customized device performance.Compared with the method using multiple manufacturing steps, this method has several advantages. First, it combines patterning and etching in one step rather than two-step nanofabrication. Secondly, it allows electronic and optical characterization before and after customization steps in a simple scheme. Lastly, pulsed FEBIE is a chemical method whose electron beam energy is lower than that of other studies (2.5 kV), which can reduce sample damage and prevent the distortion of MoS2 lattice. Because of these advantages, Granados et al. proposed nanoscissors. It is a significant alternative to expensive and time-consuming nanofabrication technologies, and has great potential for customization of post-fabrication with electrical and geometric characteristics of electronic and photoelectric devices.

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