研究目的
To achieve phase-controlled synthesis of two-dimensional transition metal dichalcogenides (TMDCs), specifically MoSe2, by interface engineering to stabilize the metastable 1T’ phase on Au(111) substrates.
研究成果
Phase-controlled growth of MoSe2 was achieved through interface engineering, with 1H phase on pristine Au(111) and 1T’ phase on Se-pretreated Au(111), attributed to Mo intercalation and electron doping stabilization. Heterojunctions showed enhanced conductivity, and the method is promising for other metastable TMDCs.
研究不足
The growth is specific to Au(111) substrates and may not be directly applicable to other materials without modification. Mo pretreatment was found to be ineffective due to clustering, limiting the approach to Se pretreatment. The study focuses on MoSe2, and applicability to other TMDCs is suggested but not extensively verified.
1：Experimental Design and Method Selection:
The study uses molecular beam epitaxy (MBE) for growth, with two approaches: co-deposition of Mo and Se on pristine Au(111) or on Se-pretreated Au(111). Scanning tunnelling microscopy (STM) and spectroscopy (STS) are employed for characterization, and density functional theory (DFT) calculations are used for theoretical support.
2：1). Scanning tunnelling microscopy (STM) and spectroscopy (STS) are employed for characterization, and density functional theory (DFT) calculations are used for theoretical support. Sample Selection and Data Sources:
2. Sample Selection and Data Sources: Au(111) single crystal is used as the substrate, cleaned by Ar+ sputtering and annealing. High-purity Se and Mo sources are used.
3：List of Experimental Equipment and Materials:
Ultrahigh vacuum system, Unisoku low-temperature STM, electron-beam evaporator for Mo, Knudsen cell for Se, electro-chemically etched tungsten tips, HOPG sample for calibration, Vienna ab-initio simulation package (VASP) for DFT calculations.
4：Experimental Procedures and Operational Workflow:
Substrate cleaning, Se pretreatment (deposition at 650°C to form reconstruction), Mo and Se co-deposition at 650°C with flux ratio 1:4, in-situ transfer to STM chamber, STM/STS measurements at
5：4 K, DFT calculations for energy and charge analysis. Data Analysis Methods:
STM images analyzed using WSxM software, STS spectra measured with lock-in techniques, DFT calculations with specific parameters (energy cutoff 400 eV, k-mesh sampling, relaxation criteria).
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