Modification of monolayer-thick semiconductors by ultra-low energy ion implantation
von Manuel Auge
Datum der mündl. Prüfung:2022-01-27
Erschienen:2022-03-08
Betreuer:Prof. Dr. Hans Christian Hofsäss
Gutachter:Prof. Dr. Hans Christian Hofsäss
Gutachter:PD Dr. Martin Wenderoth
Dateien
Name:PhD_Thesis_Auge.pdf
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Format:PDF
Zusammenfassung
Englisch
In this thesis, ultra-low energy (ULE) ion implantation is used to modify 2D materials such as graphene and transition metal dichalcogenides (TMDs). The existing implantation system is improved in two respects. By developing a sputter ion source, the list of implantable elements is expanded to include elements with high melting point and low vapour pressure. Further, the implantation stage and sample holder is extended to enable a lateral controlled ULE ion implantation using deposited electrodes on the sample or bronze plates. Based on the incorporation of noble gases into CVD grown graphene, the influence of implantation energy and fluence on the introduced defects in the host lattice is investigated. Moreover, graphene is irradiated with Mn as a model case of a magnetic dopant. It is shown that the implantation method for graphene is applicable to TMDs as well, by incorporating Se into MoS2. By establishing Se irradiation at elevated temperatures, a reproducible process for TMD modification is developed. The investigation of Cr implanted MoS2 demonstrates that substitutional exchange in the transition metal sublattice is possible.
Keywords: 2D semiconductors; Graphene; TMDs; Ultra-low energy ion implantation; Ion optics simulation; Electrostatic masking