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Title: Low-temperature anomalies of a vapor deposited glass

Authors:
; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1418401
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review Materials
Additional Journal Information:
Journal Volume: 2; Journal Issue: 1; Related Information: CHORUS Timestamp: 2018-01-29 11:11:52; Journal ID: ISSN 2475-9953
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Seoane, Beatriz, Reid, Daniel R., de Pablo, Juan J., and Zamponi, Francesco. Low-temperature anomalies of a vapor deposited glass. United States: N. p., 2018. Web. doi:10.1103/PhysRevMaterials.2.015602.
Seoane, Beatriz, Reid, Daniel R., de Pablo, Juan J., & Zamponi, Francesco. Low-temperature anomalies of a vapor deposited glass. United States. doi:10.1103/PhysRevMaterials.2.015602.
Seoane, Beatriz, Reid, Daniel R., de Pablo, Juan J., and Zamponi, Francesco. 2018. "Low-temperature anomalies of a vapor deposited glass". United States. doi:10.1103/PhysRevMaterials.2.015602.
@article{osti_1418401,
title = {Low-temperature anomalies of a vapor deposited glass},
author = {Seoane, Beatriz and Reid, Daniel R. and de Pablo, Juan J. and Zamponi, Francesco},
abstractNote = {},
doi = {10.1103/PhysRevMaterials.2.015602},
journal = {Physical Review Materials},
number = 1,
volume = 2,
place = {United States},
year = 2018,
month = 1
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on January 29, 2019
Publisher's Accepted Manuscript

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  • Al{sub 2}O{sub 3} [20 nm, atomic layer deposition (ALD)] and SiO films' [25 nm, physical vacuum deposition (PVD)] single barriers as well as hybrid barriers of the Al{sub 2}O{sub 3}/SiO or SiO/Al{sub 2}O{sub 3} have been deposited onto single 100 nm thick tris-(8-hydroxyquinoline) aluminum (AlQ{sub 3}) organic films made onto silicon wafers. The defects in the different barrier layers could be easily observed as nonfluorescent AlQ{sub 3} black spots, under ultraviolet light on the different systems stored into accelerated aging conditions (85 °C/85% RH, ∼2000 h). It has been observed that all devices containing an Al{sub 2}O{sub 3} layer present a lag time τ frommore » which defect densities of the different systems start to increase significantly. This is coherent with the supposed pinhole-free nature of fresh, ALD-deposited, Al{sub 2}O{sub 3} films. For t > τ, the number of defect grows linearly with storage time. For devices with the single Al{sub 2}O{sub 3} barrier layer, τ has been estimated to be 64 h. For t > τ, the defect occurrence rate has been calculated to be 0.268/cm{sup 2}/h. Then, a total failure of fluorescence of the AlQ{sub 3} film appears between 520 and 670 h, indicating that the Al{sub 2}O{sub 3} barrier has been totally degraded by the hot moisture. Interestingly, the device with the hybrid barrier SiO/Al{sub 2}O{sub 3} shows the same characteristics as the device with the single Al{sub 2}O{sub 3} barrier (τ = 59 h; 0.246/cm{sup 2}/h for t > τ), indicating that Al{sub 2}O{sub 3} ALD is the factor that limits the performance of the barrier system when it is directly exposed to moisture condensation. At the end of the storage period (1410 h), the defect density for the system with the hybrid SiO/Al{sub 2}O{sub 3} barrier is 120/cm{sup 2}. The best sequence has been obtained when Al{sub 2}O{sub 3} is passivated by the SiO layer (Al{sub 2}O{sub 3}/SiO). In that case, a large lag time of 795 h and a very low defect growth rate of 0.032/cm{sup 2}/h (t > τ) have been measured. At the end of the storage test (2003 h), the defect density remains very low, i.e., only 50/cm{sup 2}. On the other hand, the device with the single PVD-deposited SiO barrier layer shows no significant lag time (τ ∼ 0), and the number of defects grows linearly from initial time with a high occurrence rate of 0.517/cm{sup 2}/h. This is coherent with the pinhole-full nature of fresh, PVD-deposited, SiO films. At intermediate times, a second regime shows a lower defect occurrence rate of 0.062/cm{sup 2}/h. At a longer time span (t > 1200 h), the SiO barrier begins to degrade, and a localized crystallization onto the oxide surface, giving rise to new defects (occurrence rate 0.461/cm{sup 2}/h), could be observed. At the end of the test (2003 h), single SiO films show a very high defect density of 600/cm{sup 2}. Interestingly, the SiO surface in the Al{sub 2}O{sub 3}/SiO device does not appeared crystallized at a high time span, suggesting that the crystallization observed on the SiO surface in the AlQ{sub 3}/SiO device rather originates into the AlQ{sub 3} layer, due to high humidity ingress on the organic layer through SiO pinholes. This has been confirmed by atomic force microscopy surface imaging of the AlQ{sub 3}/SiO surface showing a central hole in the crystallization zone with a 60 nm depth, deeper than SiO thickness (25 nm). Using the organic AlQ{sub 3} sensor, the different observations made in this work give a quantitative comparison of defects' occurrence and growth in ALD-deposited versus PVD-deposited oxide films, as well as in their combination PVD/ALD and ALD/PVD.« less
  • The temperature dependence of the electrical resistivity of nickel- copper and nickel- chromium alloys and of vapor deposited layers of nickel and palladium was measured. It was investigated by a quantitative relation between the ferromagnetic resistance anomaly and spontaneous magnetization. (tr-auth)
  • Electrochromic, crystalline WO{sub 3} films have been deposited on glass substrates at ambient temperature by an oxygen-ion-assisted technique using oxygen ion energies {ge}300 eV and oxygen ion to vapor molecule (WO{sub 3}) ratios, {gamma}{ge}2.5. After lithiation, the resulting Li{sub {ital x}}WO{sub 3} films exhibited {gt}50% reflectivity in the near infrared, and the reflectivity dispersion was fit by a Drude free-electron model, yielding the Drude parameters: plasma energy, {ital E}{sub {ital p}}=3.3 eV; and the loss (damping) parameter, {ital E}{sub {Gamma}}=1.0 eV. (The bound electron permittivity, {epsilon}{sub {ital b}}, was fixed at 4.0.) These values are comparable to those obtained withmore » WO{sub 3} films rf sputter deposited onto substrates at temperatures {gt}420 {degree}C. During the ion-assisted deposition the substrate temperature reached approximately 90 {degree}C, caused primarily by radiation from the WO{sub 3} evaporant source. This indicates that economical low-temperature substrates, such as plastics, could be used. These results suggest that practical electrochromic smart windows for energy-efficient buildings might be produced using ion-assisted deposition techniques.« less
  • The structure of erbium films of 600 nm thickness deposited onto carbon ({ital a}-C) and glass substrates at 0.55 and 2.5 nm/s deposition rates for varying substrate temperatures is investigated. The cross section and surface structures are examined by electron microscope. Energy-dispersive x-ray diffraction is utilized for the structure analysis of these films. Results are compared with the results presented in H. Savaloni, M. A. Player, E. Gu, and G. V. Marr (to be published), for erbium films on molybdenum substrates. It is found that to produce films with strong preferred orientation on glass substrates low deposition rate (0.55 nm/s)more » is favorable. This is opposite to erbium on molybdenum substrates. The grain size of erbium films produced at higher deposition rate is much larger than those at lower deposition rate. The structure of thin films has implications for performance of multilayer reflectors, and preferred orientation may have other applications to x-ray instrumentation.« less