title: Stacking of 2D electron gases in Ge probed at the atomic level and its correlation to low-temperature magnetotransport.
abstract: Stacking of two-dimensional electron gases (2DEGs) obtained by δ-doping of Ge and patterned by scanning probe lithography is a promising approach to realize ultrascaled 3D epitaxial circuits, where multiple layers of active electronic components are integrated both vertically and horizontally. We use atom probe tomography and magnetotransport to correlate the real space 3D atomic distribution of dopants in the crystal with the quantum correction to the conductivity observed at low temperatures, probing if closely stacked δ-layers in Ge behave as independent 2DEGs. We find that at a separation of 9 nm the stacked-2DEGs, while interacting, still maintain their individuality in terms of electron transport and show long phase coherence lengths (∼220 nm). Strong vertical electron confinement is crucial to this finding, resulting in an interlayer scattering time much longer (∼1000 × ) than the scattering time within the dopant plane.
authors.affiliation: School of Physics, University of New South Wales, Sydney, NSW 2052, Australia. giordano.scappucci@unsw.edu.au
authors.forename: G
authors.initials: G
authors.lastname: Scappucci
authors.forename: W M
authors.initials: WM
authors.lastname: Klesse
authors.forename: A R
authors.initials: AR
authors.lastname: Hamilton
authors.forename: G
authors.initials: G
authors.lastname: Capellini
authors.forename: D L
authors.initials: DL
authors.lastname: Jaeger
authors.forename: M R
authors.initials: MR
authors.lastname: Bischof
authors.forename: R F
authors.initials: RF
authors.lastname: Reidy
authors.forename: B P
authors.initials: BP
authors.lastname: Gorman
authors.forename: M Y
authors.initials: MY
authors.lastname: Simmons
mesh_terms: D004553:Electric Conductivity; D004579:Electron Transport; D005740:Gases / Q000737:chemistry*; D005857:Germanium / Q000737:chemistry*; D060526:Magnetic Fields; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013223:Statistics as Topic; D013696:Temperature
chemical_list: D005740:Gases; D005857:Germanium