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Title: Environmentally induced chemical and morphological heterogeneity of zinc oxide thin films

Zinc oxide (ZnO) thin films have been reported to suffer from degradation in electrical properties, when exposed to elevated heat and humidity, often leading to failures of electronic devices containing ZnO films. This degradation appears to be linked to water and oxygen penetration into the ZnO film. However, a direct observation in the ZnO film morphological evolution detailing structural and chemical changes has been lacking. Here, we systematically investigated the chemical and morphological heterogeneities of ZnO thin films caused by elevated heat and humidity, simulating an environmental aging. X-ray fluorescence microscopy, X-ray absorption spectroscopy, grazing incidence small angle and wide angle X-ray scattering, scanning electron microscopy (SEM), ultra-high-resolution SEM, and optical microscopy were carried out to examine ZnO and Al-doped ZnO thin films on two different substrates—silicon wafers and flexible polyethylene terephthalate (PET) films. In the un-doped ZnO thin film, the simulated environmental aging is resulting in pin-holes. In the Al-doped ZnO thin films, significant morphological changes occurred after the treatment, with an appearance of platelet-shaped structures that are 100–200 nm wide by 1μm long. Synchrotron x-ray characterization further confirmed the heterogeneity in the aged Al-doped ZnO, showing the formation of anisotropic structures and disordering. X-ray diffraction and X-ray absorptionmore » spectroscopy indicated the formation of a zinc hydroxide in the aged Al-doped films. In conclusion, utilizing advanced characterization methods, our studies provided information with an unprecedented level of details and revealed the chemical and morphologically heterogeneous nature of the degradation in ZnO thin films.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5] ; ORCiD logo [4] ;  [6] ;  [4]
  1. Stony Brook Univ., NY (United States). Dept. of Materials Science and Engineering
  2. Autonomous Univ. of Barcelona (UAB), Barcelona (Spain). Henkel Iberica S. A. Edificio Eureka
  3. Henkel Corp., Bridgewater, NJ (United States)
  4. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
  5. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
  6. Hitachi High Technologies America, Clarksburg, MD (United States)
Publication Date:
OSTI Identifier:
1340397
Report Number(s):
BNL-112697-2016-JA
Journal ID: ISSN 0003-6951; TRN: US1701663
Grant/Contract Number:
SC0012704; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 109; Journal Issue: 9; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE