Interface Structure and Doping of Chemical Vapor Deposition-Grown MoS2 on 4H–SiC by Microscopic Analyses and Ab Initio Calculations

Panasci, Salvatore E. and Deretzis, Ioannis and Schilirò, Emanuela and La Magna, Antonino and Roccaforte, Fabrizio and Koós, Antal Adolf and Pécz, Béla (2023) Interface Structure and Doping of Chemical Vapor Deposition-Grown MoS2 on 4H–SiC by Microscopic Analyses and Ab Initio Calculations. PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS. ISSN 1862-6254

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Abstract

The interface structure and electronic properties of monolayer (1L) MoS 2 domains grown by chemical vapor deposition on 4H–SiC(0001) are investigated by microscopic/spectroscopic analyses combined with ab initio calculations. The triangular domains are epitaxially oriented on the (0001) basal plane, with the presence of a van der Waals (vdW) gap between 1L–MoS 2 and the SiC terraces. The high crystalline quality of the domains is confirmed by photo- luminescence emission. Furthermore, a very low tensile strain ( ε � 0.03%) of 1L–MoS 2 , consistent with the small in-plane lattice mismatch, and a p-type doping of (0.45 � 0.11) � 10 13 cm�2 , is evaluated by Raman mapping. Density functional theory (DFT) calculations of the MoS 2 /4H–SiC(0001) system are also performed, considering different levels of refinement of the model: 1) the simple case of the junction between Si-terminated SiC and MoS 2 , showing a covalent bond between the Si–S atoms and n-type doping of MoS 2 ; 2) the complete passivation of Si dangling bonds with a monolayer (1 ML) of oxygen atoms, resulting in a vdW bond with d Si–S � 3.84 Å bond length and p-type doping of MoS 2 ; and 3) partial (¼ ML and ½ ML) oxygen coverages of the 4H–SiC surface, resulting in intermediate values of d Si–S and doping behavior.

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