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Radial band bending at wurtzite–zinc-blende–GaAs interfaces

Geijselaers, Irene LU ; Lehmann, Sebastian LU ; Dick, Kimberly A LU and Pistol, Mats-Erik LU (2018) In Nano Futures 2(3).
Abstract
The band offset between wurtzite (wz) and zinc-blende (zb) GaAs is an important fundamental parameter in polytype heterostructure engineering. Since the interface has a type-II band alignment, it is reasonably straightforward to measure the band offset using photoluminescence (PL) e.g. on nanowires containing heterostructures between wz and zb GaAs. It has, however, been found that the transition energy in such heterostructures depends on the diameter of the nanowires which introduces uncertainties in the determined value of the band offset. In order to extract a more accurate value and to further elucidate the diameter-dependent behavior of the transition energy we have performed PL studies on a large set of GaAs nanowires. Those... (More)
The band offset between wurtzite (wz) and zinc-blende (zb) GaAs is an important fundamental parameter in polytype heterostructure engineering. Since the interface has a type-II band alignment, it is reasonably straightforward to measure the band offset using photoluminescence (PL) e.g. on nanowires containing heterostructures between wz and zb GaAs. It has, however, been found that the transition energy in such heterostructures depends on the diameter of the nanowires which introduces uncertainties in the determined value of the band offset. In order to extract a more accurate value and to further elucidate the diameter-dependent behavior of the transition energy we have performed PL studies on a large set of GaAs nanowires. Those nanowires have different diameters and contain one wz–GaAs segment embedded in otherwise zb–GaAs. We have also studied the effect of a passivating capping layer of AlAs on the determined band offset. We find that our data is well explained by a diameter-dependent radial band bending in the nanowires. Combining modeling of the band bending with the experimental data we extract a band offset of about 125 meV and a p-type doping concentration of 1016 cm−3. Our results will improve the accuracy of future modeling of the electronic properties of wz–zb GaAs heterostructures and other engineered polytypic materials. (Less)
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author
organization
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publication status
published
subject
in
Nano Futures
volume
2
issue
3
publisher
IOP Publishing Ltd.
ISSN
2399-1984
DOI
10.1088/2399-1984/aac96c
language
English
LU publication?
yes
id
f037f948-2f2a-442a-8cd2-9f0b09beafcd
date added to LUP
2019-03-27 10:02:33
date last changed
2019-03-29 09:03:33
@article{f037f948-2f2a-442a-8cd2-9f0b09beafcd,
  abstract     = {The band offset between wurtzite (wz) and zinc-blende (zb) GaAs is an important fundamental parameter in polytype heterostructure engineering. Since the interface has a type-II band alignment, it is reasonably straightforward to measure the band offset using photoluminescence (PL) e.g. on nanowires containing heterostructures between wz and zb GaAs. It has, however, been found that the transition energy in such heterostructures depends on the diameter of the nanowires which introduces uncertainties in the determined value of the band offset. In order to extract a more accurate value and to further elucidate the diameter-dependent behavior of the transition energy we have performed PL studies on a large set of GaAs nanowires. Those nanowires have different diameters and contain one wz–GaAs segment embedded in otherwise zb–GaAs. We have also studied the effect of a passivating capping layer of AlAs on the determined band offset. We find that our data is well explained by a diameter-dependent radial band bending in the nanowires. Combining modeling of the band bending with the experimental data we extract a band offset of about 125 meV and a p-type doping concentration of 1016 cm−3. Our results will improve the accuracy of future modeling of the electronic properties of wz–zb GaAs heterostructures and other engineered polytypic materials.},
  author       = {Geijselaers, Irene and Lehmann, Sebastian and Dick, Kimberly A and Pistol, Mats-Erik},
  issn         = {2399-1984},
  language     = {eng},
  number       = {3},
  publisher    = {IOP Publishing Ltd.},
  series       = {Nano Futures},
  title        = {Radial band bending at wurtzite–zinc-blende–GaAs interfaces},
  url          = {http://dx.doi.org/10.1088/2399-1984/aac96c},
  volume       = {2},
  year         = {2018},
}