The Library
Data for Indirect to direct gap crossover in two-dimensional InSe revealed by angle resolved photoemission spectroscopy
Tools
Hamer, Matthew, Zultak, Johanna, Tyurnina, Anastasia V., Zólyomi, Viktor, Terry, Daniel, Barinov, Alexei, Garner, Alistair, Donoghue, Jack, Rooney, Aidan P., Kandyba, Viktor, Giampietri, Alessio, Graham, Abigail J., Teutsch, Natalie C., Xia, Xue, Koperski, Maciej, Haigh, Sarah J., Fal'ko, Vladimir I., Gorbachev, Roman and Wilson, Neil R. (2019) Data for Indirect to direct gap crossover in two-dimensional InSe revealed by angle resolved photoemission spectroscopy. [Dataset]
Archive (ZIP) (Zip archive)
111770 Data folder.zip - Published Version Available under License Creative Commons Attribution 4.0. Download (3916Kb) |
|
Plain Text (Readme file)
ARPES data description.txt - Published Version Available under License Creative Commons Attribution 4.0. Download (3274b) |
Abstract
Atomically thin films of III–VI post-transition metal chalcogenides (InSe and GaSe) form an interesting class of two-dimensional semiconductors that feature a strong variation of their band gap as a function of the number of layers in the crystal and, specifically for InSe, an expected crossover from a direct gap in the bulk to a weakly indirect band gap in monolayers and bilayers. Here, we apply angle-resolved photoemission spectroscopy with submicrometer spatial resolution (μARPES) to visualize the layer-dependent valence band structure of mechanically exfoliated crystals of InSe. We show that for one-layer and two-layer InSe the valence band maxima are away from the Γ-point, forming an indirect gap, with the conduction band edge known to be at the Γ-point. In contrast, for six or more layers the band gap becomes direct, in good agreement with theoretical predictions. The high-quality monolayer and bilayer samples enable us to resolve, in the photoluminescence spectra, the band-edge exciton (A) from the exciton (B) involving holes in a pair of deeper valence bands, degenerate at Γ, with a splitting that agrees with both μARPES data and the results of DFT modeling. Due to the difference in symmetry between these two valence bands, light emitted by the A-exciton should be predominantly polarized perpendicular to the plane of the two-dimensional crystal, which we have verified for few-layer InSe crystals.
Item Type: | Dataset | |||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Subjects: | Q Science > QC Physics | |||||||||||||||||||||||||||||||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Physics | |||||||||||||||||||||||||||||||||
Type of Data: | Experimental data | |||||||||||||||||||||||||||||||||
Library of Congress Subject Headings (LCSH): | Photoelectron spectroscopy -- Research, Photoemission, Oxide minerals -- Synthesis | |||||||||||||||||||||||||||||||||
Publisher: | University of Warwick, Department of Physics | |||||||||||||||||||||||||||||||||
Official Date: | 24 January 2019 | |||||||||||||||||||||||||||||||||
Dates: |
|
|||||||||||||||||||||||||||||||||
Status: | Not Peer Reviewed | |||||||||||||||||||||||||||||||||
Publication Status: | Published | |||||||||||||||||||||||||||||||||
Media of Output (format): | .txt | |||||||||||||||||||||||||||||||||
Access rights to Published version: | Open Access (Creative Commons) | |||||||||||||||||||||||||||||||||
Copyright Holders: | University of Warwick | |||||||||||||||||||||||||||||||||
Description: | Data description for ‘Indirect to direct gap crossover in two-dimensional InSe revealed by ARPES’ The photoluminescence and DFT data and headings in the files are self-explanatory (contact the corresponding authors if in doubt). Further details are given in the accompanying readme for the ARPES data files. |
|||||||||||||||||||||||||||||||||
Date of first compliant deposit: | 5 February 2019 | |||||||||||||||||||||||||||||||||
Date of first compliant Open Access: | 2 March 2020 | |||||||||||||||||||||||||||||||||
RIOXX Funder/Project Grant: |
|
|||||||||||||||||||||||||||||||||
Related URLs: | ||||||||||||||||||||||||||||||||||
Contributors: |
|
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |
Downloads
Downloads per month over past year