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HL: Fachverband Halbleiterphysik

HL 27: 2D semiconductors and van der Waals heterostructures III (joint session HL/DS)

HL 27.8: Vortrag

Dienstag, 17. März 2020, 12:00–12:15, POT 81

Chemical Trend of Transition-Metal Doping in WSe₂ — •Dan Han^1,2,3, Shiyou Chen¹, and Mao-Hua Du² — ¹East China Normal University, Shanghai, China — ²Oak Ridge National Laboratory, Oak Ridge, USA — ³Ludwig-Maximilians-Universität München, Munich, Germany

Transition-metal dichalcogenides (TMDs) are promising nanoscale materials with a wide range of applications. Chemical doping is a powerful tool for tailoring the physical and chemical properties of TMDs for targeted functionalities. As an important TMD, WSe₂ has great potential for applications in FET and CMOS technologies. However, precise control over the type and density of free carriers remains challenging. We performed first-principles calculations to study intrinsic defects and transition-metal (TM) dopants in WSe₂. Our results show that TM doping can effectively control the Fermi level in WSe₂ with no significant compensation by intrinsic defects. Nb and Ta are effective p-type dopants capable of generating a high free hole density in WSe₂. While n-type doping is possible by Re and Cu, the doping efficiency is reduced due to the lower attainable dopant concentration and higher ionization energies. The chemical trend in the attainable concentration of various substitutional TM dopants in WSe₂ is largely determined by the competition between the dopant incorporation in WSe₂ and the formation of the secondary phase TMSe₂. Such a competition is strongly affected by the different crystal environments of the TM ion in TMSe₂ and WSe₂.