Limits...
Cohesive strength of nanocrystalline ZnO:Ga thin films deposited at room temperature.

Samantilleke AP, Rebouta LM, Garim V, Rubio-Peña L, Lanceros-Mendez S, Alpuim P, Carvalho S, Kudrin AV, Danilov YA - Nanoscale Res Lett (2011)

Bottom Line: The COS is similar for different GZO coatings and occurs for nominal strains approx. 1%.The cohesive strength of coatings, which was evaluated from the initial part of the crack density evolution, was found to be between 1.3 and 1.4 GPa.For these calculations, a Young's modulus of 112 GPa was used, evaluated by nanoindentation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centro de Física, Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal. anura@fisica.uminho.pt.

ABSTRACT
In this study, transparent conducting nanocrystalline ZnO:Ga (GZO) films were deposited by dc magnetron sputtering at room temperature on polymers (and glass for comparison). Electrical resistivities of 8.8 × 10-4 and 2.2 × 10-3 Ω cm were obtained for films deposited on glass and polymers, respectively. The crack onset strain (COS) and the cohesive strength of the coatings were investigated by means of tensile testing. The COS is similar for different GZO coatings and occurs for nominal strains approx. 1%. The cohesive strength of coatings, which was evaluated from the initial part of the crack density evolution, was found to be between 1.3 and 1.4 GPa. For these calculations, a Young's modulus of 112 GPa was used, evaluated by nanoindentation.

No MeSH data available.


Related in: MedlinePlus

Cracking density as a function of the substrate nominal strain for different GZO coatings deposited on PEN (82 μm) and the crack density evolution of the PEN/GZO coatings.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211395&req=5

Figure 4: Cracking density as a function of the substrate nominal strain for different GZO coatings deposited on PEN (82 μm) and the crack density evolution of the PEN/GZO coatings.

Mentions: Tensile tests were performed at a constant strain rate on PEN substrates (82 μm) coated with GZO films (approx. 100 nm) prepared under two different Pws to increase nominal strains. The PEN substrate is isotropic, and the elastic modulus was 4.23 GPa, as measured through the tensile test on uncoated substrate. The cracking densities as a function of the substrate nominal strain for two different GZO coatings (0.53 and 0.86 Pa) are shown in Figure 4a. The crack densities at saturation of these two PEN/GZO films were 0.316 and 0.515 μm-1, respectively. The coatings have similar properties and thicknesses, with small differences causing variations wholly within acceptable margins of error. Using the weakest link model, the coating's cohesive strength was evaluated from the early stages of the fragmentation process, assuming a Weibull-type, size-dependent probability of failure for the coating fragments of length ℓ under a stress σ [12,13]:(2)


Cohesive strength of nanocrystalline ZnO:Ga thin films deposited at room temperature.

Samantilleke AP, Rebouta LM, Garim V, Rubio-Peña L, Lanceros-Mendez S, Alpuim P, Carvalho S, Kudrin AV, Danilov YA - Nanoscale Res Lett (2011)

Cracking density as a function of the substrate nominal strain for different GZO coatings deposited on PEN (82 μm) and the crack density evolution of the PEN/GZO coatings.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211395&req=5

Figure 4: Cracking density as a function of the substrate nominal strain for different GZO coatings deposited on PEN (82 μm) and the crack density evolution of the PEN/GZO coatings.
Mentions: Tensile tests were performed at a constant strain rate on PEN substrates (82 μm) coated with GZO films (approx. 100 nm) prepared under two different Pws to increase nominal strains. The PEN substrate is isotropic, and the elastic modulus was 4.23 GPa, as measured through the tensile test on uncoated substrate. The cracking densities as a function of the substrate nominal strain for two different GZO coatings (0.53 and 0.86 Pa) are shown in Figure 4a. The crack densities at saturation of these two PEN/GZO films were 0.316 and 0.515 μm-1, respectively. The coatings have similar properties and thicknesses, with small differences causing variations wholly within acceptable margins of error. Using the weakest link model, the coating's cohesive strength was evaluated from the early stages of the fragmentation process, assuming a Weibull-type, size-dependent probability of failure for the coating fragments of length ℓ under a stress σ [12,13]:(2)

Bottom Line: The COS is similar for different GZO coatings and occurs for nominal strains approx. 1%.The cohesive strength of coatings, which was evaluated from the initial part of the crack density evolution, was found to be between 1.3 and 1.4 GPa.For these calculations, a Young's modulus of 112 GPa was used, evaluated by nanoindentation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centro de Física, Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal. anura@fisica.uminho.pt.

ABSTRACT
In this study, transparent conducting nanocrystalline ZnO:Ga (GZO) films were deposited by dc magnetron sputtering at room temperature on polymers (and glass for comparison). Electrical resistivities of 8.8 × 10-4 and 2.2 × 10-3 Ω cm were obtained for films deposited on glass and polymers, respectively. The crack onset strain (COS) and the cohesive strength of the coatings were investigated by means of tensile testing. The COS is similar for different GZO coatings and occurs for nominal strains approx. 1%. The cohesive strength of coatings, which was evaluated from the initial part of the crack density evolution, was found to be between 1.3 and 1.4 GPa. For these calculations, a Young's modulus of 112 GPa was used, evaluated by nanoindentation.

No MeSH data available.


Related in: MedlinePlus