Electronic Structure Changes Due to Crystal Phase Switching at the Atomic Scale Limit
Knutsson, Johan Valentin LU ; Lehmann, Sebastian LU ; Hjort, Martin LU
; Lundgren, Edvin
LU
; Dick, Kimberly A.
LU
; Timm, Rainer
LU
and Mikkelsen, Anders
LU
(2017)
In ACS Nano
11(10).
p.10519-10528
- Abstract
The perfect switching between crystal phases with different electronic structure in III-V nanowires allows for the design of superstructures with quantum wells only a single atomic layer wide. However, it has only been indirectly inferred how the electronic structure will vary down to the smallest possible crystal segments. We use low-temperature scanning tunneling microscopy and spectroscopy to directly probe the electronic structure of Zinc blende (Zb) segments in Wurtzite (Wz) InAs nanowires with atomic-scale precision. We find that the major features in the band structure change abruptly down to a single atomic layer level. Distinct Zb electronic structure signatures are observed on both the conduction and valence band sides for the... (More)
The perfect switching between crystal phases with different electronic structure in III-V nanowires allows for the design of superstructures with quantum wells only a single atomic layer wide. However, it has only been indirectly inferred how the electronic structure will vary down to the smallest possible crystal segments. We use low-temperature scanning tunneling microscopy and spectroscopy to directly probe the electronic structure of Zinc blende (Zb) segments in Wurtzite (Wz) InAs nanowires with atomic-scale precision. We find that the major features in the band structure change abruptly down to a single atomic layer level. Distinct Zb electronic structure signatures are observed on both the conduction and valence band sides for the smallest possible Zb segment: a single InAs bilayer. We find evidence of confined states in the region of both single and double bilayer Zb segments indicative of the formation of crystal segment quantum wells due to the smaller band gap of Zb as compared to Wz. In contrast to the internal electronic structure of the nanowire, surface states located in the band gap were found to be only weakly influenced by the presence of the smallest Zb segments. Our findings directly demonstrate the feasibility of crystal phase switching for the ultimate limit of atomistic band structure engineering of quantum confined structures. Further, it indicates that band gap values obtained for the bulk are reasonable to use even for the smallest crystal segments. However, we also find that the suppression of surface and interface states could be necessary in the use of this effect for engineering of future electronic devices.
(Less)
- author
- Knutsson, Johan Valentin
LU
; Lehmann, Sebastian
LU
; Hjort, Martin
LU
; Lundgren, Edvin
LU
; Dick, Kimberly A.
LU
; Timm, Rainer
LU
and Mikkelsen, Anders
LU
- organization
- publishing date
- 2017-10-24
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- crystal phase, electronic structure, InAs, nanowire, STM/S, wurtzite, zinc blende
- in
- ACS Nano
- volume
- 11
- issue
- 10
- pages
- 10 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:85033470415
- pmid:28960985
- wos:000413992800099
- ISSN
- 1936-0851
- DOI
- 10.1021/acsnano.7b05873
- language
- English
- LU publication?
- yes
- id
- 0f1bff08-9d8e-41b5-ade2-4fe8e5e4af1f
- date added to LUP
- 2017-11-21 07:48:42
- date last changed
- 2024-06-11 06:19:58
@article{0f1bff08-9d8e-41b5-ade2-4fe8e5e4af1f,
abstract = {{<p>The perfect switching between crystal phases with different electronic structure in III-V nanowires allows for the design of superstructures with quantum wells only a single atomic layer wide. However, it has only been indirectly inferred how the electronic structure will vary down to the smallest possible crystal segments. We use low-temperature scanning tunneling microscopy and spectroscopy to directly probe the electronic structure of Zinc blende (Zb) segments in Wurtzite (Wz) InAs nanowires with atomic-scale precision. We find that the major features in the band structure change abruptly down to a single atomic layer level. Distinct Zb electronic structure signatures are observed on both the conduction and valence band sides for the smallest possible Zb segment: a single InAs bilayer. We find evidence of confined states in the region of both single and double bilayer Zb segments indicative of the formation of crystal segment quantum wells due to the smaller band gap of Zb as compared to Wz. In contrast to the internal electronic structure of the nanowire, surface states located in the band gap were found to be only weakly influenced by the presence of the smallest Zb segments. Our findings directly demonstrate the feasibility of crystal phase switching for the ultimate limit of atomistic band structure engineering of quantum confined structures. Further, it indicates that band gap values obtained for the bulk are reasonable to use even for the smallest crystal segments. However, we also find that the suppression of surface and interface states could be necessary in the use of this effect for engineering of future electronic devices.</p>}},
author = {{Knutsson, Johan Valentin and Lehmann, Sebastian and Hjort, Martin and Lundgren, Edvin and Dick, Kimberly A. and Timm, Rainer and Mikkelsen, Anders}},
issn = {{1936-0851}},
keywords = {{crystal phase; electronic structure; InAs; nanowire; STM/S; wurtzite; zinc blende}},
language = {{eng}},
month = {{10}},
number = {{10}},
pages = {{10519--10528}},
publisher = {{The American Chemical Society (ACS)}},
series = {{ACS Nano}},
title = {{Electronic Structure Changes Due to Crystal Phase Switching at the Atomic Scale Limit}},
url = {{http://dx.doi.org/10.1021/acsnano.7b05873}},
doi = {{10.1021/acsnano.7b05873}},
volume = {{11}},
year = {{2017}},
}