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Hybrid ZnO/GaN distributed Bragg reflectors grown by plasma-assisted molecular beam epitaxy

Adolph, David LU ; Zamani, Reza R. LU ; Dick, Kimberly A. LU and Ive, Tommy (2016) In APL Materials 4(8).
Abstract

We demonstrate crack-free ZnO/GaN distributed Bragg reflectors (DBRs) grown by hybrid plasma-assisted molecular beam epitaxy using the same growth chamber for continuous growth of both ZnO and GaN without exposure to air. This is the first time these ZnO/GaN DBRs have been demonstrated. The Bragg reflectors consisted up to 20 periods as shown with cross-sectional transmission electron microscopy. The maximum achieved reflectance was 77% with a 32 nm wide stopband centered at 500 nm. Growth along both (0001) and (000 1) directions was investigated. Low-temperature growth as well as two-step low/high-temperature deposition was carried out where the latter method improved the DBR reflectance. Samples grown along the (0001) direction... (More)

We demonstrate crack-free ZnO/GaN distributed Bragg reflectors (DBRs) grown by hybrid plasma-assisted molecular beam epitaxy using the same growth chamber for continuous growth of both ZnO and GaN without exposure to air. This is the first time these ZnO/GaN DBRs have been demonstrated. The Bragg reflectors consisted up to 20 periods as shown with cross-sectional transmission electron microscopy. The maximum achieved reflectance was 77% with a 32 nm wide stopband centered at 500 nm. Growth along both (0001) and (000 1) directions was investigated. Low-temperature growth as well as two-step low/high-temperature deposition was carried out where the latter method improved the DBR reflectance. Samples grown along the (0001) direction yielded a better surface morphology as revealed by scanning electron microscopy and atomic force microscopy. Reciprocal space maps showed that ZnO(000 1)/GaN reflectors are relaxed whereas the ZnO(0001)/GaN DBRs are strained. The ability to n-type dope ZnO and GaN makes the ZnO(0001)/GaN DBRs interesting for various optoelectronic cavity structures.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
APL Materials
volume
4
issue
8
publisher
American Institute of Physics
external identifiers
  • scopus:84982095517
  • wos:000383910000007
ISSN
2166-532X
DOI
10.1063/1.4960619
language
English
LU publication?
yes
id
85353f67-69e0-4215-b7e7-7270696df86e
date added to LUP
2016-12-09 14:46:01
date last changed
2017-04-23 04:55:59
@article{85353f67-69e0-4215-b7e7-7270696df86e,
  abstract     = {<p>We demonstrate crack-free ZnO/GaN distributed Bragg reflectors (DBRs) grown by hybrid plasma-assisted molecular beam epitaxy using the same growth chamber for continuous growth of both ZnO and GaN without exposure to air. This is the first time these ZnO/GaN DBRs have been demonstrated. The Bragg reflectors consisted up to 20 periods as shown with cross-sectional transmission electron microscopy. The maximum achieved reflectance was 77% with a 32 nm wide stopband centered at 500 nm. Growth along both (0001) and (000 1) directions was investigated. Low-temperature growth as well as two-step low/high-temperature deposition was carried out where the latter method improved the DBR reflectance. Samples grown along the (0001) direction yielded a better surface morphology as revealed by scanning electron microscopy and atomic force microscopy. Reciprocal space maps showed that ZnO(000 1)/GaN reflectors are relaxed whereas the ZnO(0001)/GaN DBRs are strained. The ability to n-type dope ZnO and GaN makes the ZnO(0001)/GaN DBRs interesting for various optoelectronic cavity structures.</p>},
  articleno    = {086106},
  author       = {Adolph, David and Zamani, Reza R. and Dick, Kimberly A. and Ive, Tommy},
  issn         = {2166-532X},
  language     = {eng},
  month        = {08},
  number       = {8},
  publisher    = {American Institute of Physics},
  series       = {APL Materials},
  title        = {Hybrid ZnO/GaN distributed Bragg reflectors grown by plasma-assisted molecular beam epitaxy},
  url          = {http://dx.doi.org/10.1063/1.4960619},
  volume       = {4},
  year         = {2016},
}