Modulation doping and charge density wave transition in layered PbSe–VSe 2 ferecrystal heterostructures

Controlling charge carrier concentrations remains a major challenge in the application of quasi-two-dimensional materials. A promising approach is the modulation doping of transport channels via charge transfer from neighboring layers in stacked heterostructures. Ferecrystals, which are metastable l...

Full description

Saved in:
Bibliographic Details
Published in:Nanoscale 2022-07, Vol.14 (28), p.10143-10154
Main Authors: Göhler, Fabian, Ramasubramanian, Shrinidhi, Rajak, Sanam Kumari, Rösch, Niels, Schütze, Adrian, Wolff, Susanne, Cordova, Dmitri Leo Mesoza, Johnson, David C., Seyller, Thomas
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Controlling charge carrier concentrations remains a major challenge in the application of quasi-two-dimensional materials. A promising approach is the modulation doping of transport channels via charge transfer from neighboring layers in stacked heterostructures. Ferecrystals, which are metastable layered structures created from artificial elemental precursors, are a perfect model system to investigate modulation doping, as they offer unparalleled freedom in the combination of different constituents and variable layering sequences. In this work, differently stacked combinations of rock-salt structured PbSe and VSe 2 were investigated using X-ray photoelectron spectroscopy. The PbSe layers act as electron donors in all heterostructures, with about 0.1 to 0.3 donated electrons per VSe 2 unit cell. While they initially retain their inherent semiconducting behavior, they themselves become metallic when combined with a larger number of VSe 2 layers, as evidenced by a change of the XPS core level lineshape. Additional analysis of the valence band structure was performed for selected stacking orders at different sample temperatures to investigate a predicted charge density wave (CDW) transition. While there appear to be hints of a gap opening, the data so far is inconclusive and the application of spatially resolved techniques such as scanning tunneling microscopy is encouraged for further studies.
ISSN:2040-3364
2040-3372
DOI:10.1039/D2NR01071B