Understanding the\nEffect of Electron Irradiation on\nWS<sub>2</sub> Nanotube Devices to Improve Prototyping Routines

To satisfy the needs of the current technological world\nthat demands\nhigh performance and efficiency, a deep understanding of the whole\nfabrication process of electronic devices based on low-dimensional\nmaterials is necessary for rapid prototyping of devices. The fabrication\nprocesses of such nanoscale devices often include exposure to an electron\nbeam. A field effect transistor (FET) is a core device in current\ncomputation technology, and FET configuration is also commonly used\nfor extraction of electronic properties of low-dimensional materials.\nIn this experimental study, we analyze the effect of electron beam\nexposure on electrical properties of individual WS<sub>2</sub> nanotubes\nin the FET configuration by in-operando transport measurements inside\na scanning electron microscope. Upon exposure to the electron beam,\nwe observed a significant change in the resistance of individual substrate-supported\nnanotubes (by a factor of 2 to 14) that was generally irreversible.\nThe resistance of each nanotube did not return to its original state\neven after keeping it under ambient conditions for hours to days.\nFurthermore, we employed Kelvin probe force microscopy to monitor\nsurface potential and identified that substrate charging is the primary\ncause of changes in nanotubes’ resistance. Hence, extra care\nshould be taken when analyzing nanostructures in contact with insulating\noxides that are subject to electron exposure during or after fabrication.