研究目的
Investigating the nanoscale origin of strain and carrier concentration in graphene-hexagonal boron nitride (hBN) heterostructures on silicon dioxide (SiO2).
研究成果
The study demonstrates that nanoscale variations in strain and charge in graphene-hBN heterostructures arise from local features such as fractures, folds, edges, and bubbles. Raman spectroscopy combined with confocal mapping provides a non-invasive tool for probing arbitrary strains and doping in graphene at the nanoscale, revealing variations in physical parameters not accessible by other methods.
研究不足
The method is only valid for the case of undoped or p-type graphene. High defect densities can interfere with the separation of strain and doping contributions. The model may return negative values of n for particular Raman measurements, which are difficult to interpret.
1：Experimental Design and Method Selection:
Confocal Raman microscopy and a vector analysis scheme were used to investigate strain and carrier concentration in graphene-hBN heterostructures. The study focused on two types of heterostructures: graphene on SiO2 partially covered by hBN, and graphene fully encapsulated between two hBN flakes.
2：Sample Selection and Data Sources:
Exfoliated graphene-hBN heterostructures on SiO2 were studied. AFM scans and Raman maps were taken to analyze the heterostructures.
3：List of Experimental Equipment and Materials:
A Renishaw inVia confocal Raman microscope with a 532 nm excitation laser focused through a 100× objective was used for Raman measurements. AFM measurements were performed with a Bruker Dimension Icon scanning probe microscope.
4：Experimental Procedures and Operational Workflow:
Raman measurements were performed in high confocality mode with a laser power incident on the sample of ~10 mW. AFM measurements were performed using Peak Force tapping mode.
5：Data Analysis Methods:
Lorentzians were fitted to the graphene 2D, G and D peaks, and the characteristic hBN peak for every spectrum. The fitted intensities of the 2D and hBN peaks were used to determine points corresponding to graphene and hBN.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
