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Robust quantum point contact operation of narrow graphene constrictions patterned by AFM cleavage lithography.
- Source :
- NPJ 2D Materials & Applications; 12/7/2020, Vol. 4 Issue 1, p1-6, 6p
- Publication Year :
- 2020
-
Abstract
- Detecting conductance quantization in graphene nanostructures turned out more challenging than expected. The observation of well-defined conductance plateaus through graphene nanoconstrictions so far has only been accessible in the highest quality suspended or h-BN encapsulated devices. However, reaching low conductance quanta in zero magnetic field, is a delicate task even with such ultra-high mobility devices. Here, we demonstrate a simple AFM-based nanopatterning technique for defining graphene constrictions with high precision (down to 10 nm width) and reduced edge-roughness (+/−1 nm). The patterning process is based on the in-plane mechanical cleavage of graphene by the AFM tip, along its high symmetry crystallographic directions. As-defined, narrow graphene constrictions with improved edge quality enable an unprecedentedly robust QPC operation, allowing the observation of conductance quantization even on standard SiO<subscript>2</subscript>/Si substrates, down to low conductance quanta. Conductance plateaus, were observed at n × e<superscript>2</superscript>/h, evenly spaced by 2 × e<superscript>2</superscript>/h (corresponding to n = 3, 5, 7, 9, 11) in the absence of an external magnetic field, while spaced by e<superscript>2</superscript>/h (n = 1, 2, 3, 4, 5, 6) in 8 T magnetic field. [ABSTRACT FROM AUTHOR]
- Subjects :
- GRAPHENE
LITHOGRAPHY
QUANTUM mechanics
SURFACE roughness
ROBUST control
Subjects
Details
- Language :
- English
- ISSN :
- 23977132
- Volume :
- 4
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- NPJ 2D Materials & Applications
- Publication Type :
- Academic Journal
- Accession number :
- 147456241
- Full Text :
- https://doi.org/10.1038/s41699-020-00177-x