Structure and stimulated emission of a high-quality zinc oxide epilayer grown by atomic layer deposition on the sapphire substrate

Chen, H.C.; Chen, M.J.; Liu, Tien‐Chen; Yang, Jer−Ren; Shiojiri, Makoto

doi:10.1016/j.tsf.2010.07.069

Cited by 20 publications

(17 citation statements)

References 40 publications

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“…19 Resistivity in the range of 10 À3 X cm was observed for a small addition of aluminum (Al). 17 Low temperature ALD growth and post-deposition rapid thermal annealing of the ZnO epilayer deposited on a c-Al 2 O 3 substrate was recently reported by Chen et al 21 They found that the ZnO epilayer was highly c-axis oriented, and the high resolution TEM imaging showed no columnar structure, which is a signature of ALD growth. 19,20 However for longer cycle times growth rates from 2.22 to 4.3 Å /cycle are observed for AZO.…”

Section: Introductionmentioning

confidence: 85%

Growth morphology and electrical/optical properties of Al-doped ZnO thin films grown by atomic layer deposition

Dhakal

Vanhart

Christian

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The authors report electrical and optical characterization of zinc oxide (ZnO) and Al-doped zinc oxide (AZO) films grown by atomic layer deposition (ALD). A detailed analysis of ZnO growth morphology is presented with the help of atomic force microscopy imaging, roughness analysis, and x-ray photoelectron spectroscopy surface chemistry information. Initially the film grew as islands, which coalesced to complete the substrate coverage at 50 ALD cycles. The AZO films to be used as transparent conducting oxides for solar cell applications were grown on single crystalline Si (100) and float-glass substrates at temperatures from 150–325 °C. The amount of aluminum doping was varied from 2 to 8 %. The AZO film with 5% Al exhibited the highest conductivity in the film, which increased as the growth temperature increased. Hall effect measurements of an AZO film of thickness 575 nm doped at 5% on silicon and glass substrates showed a sheet resistance (Rs) of 100 Ω/□, which improved further to 25 Ω/□ after annealing at higher temperatures in an argon-hydrogen environment. The transmittance and reflectance of the films grown on glass substrates were used to calculate the band gap. The band gap of AZO increased with Al-doping level. The transmittance of the films in the entire 0 to 8 % doping range, was found to be 80 to 90 % in the visible region. In addition, the growth rates of ZnO, Al2O3, and AZO films were also studied. The growth rate of the AZO films was 1.95 Å per ALD cycle with a cycle time of 1 s. This growth rate is relatively large for an ALD process. The interface of the AZO-Al2O3-Si(100) imaged using high resolution transmission electron microscopy showed a random texture and a continuous interface.

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Section: Introductionmentioning

confidence: 85%

Growth morphology and electrical/optical properties of Al-doped ZnO thin films grown by atomic layer deposition

Dhakal

Vanhart

Christian

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…Some other practical advantages of ALD include excellent conformity, high uniformity over a large area, and good reproducibility . In addition, the high chemical reactivity of precursors used in ALD allows deposition of ZnO films at considerably lower temperatures compared with temperatures applied in some other deposition techniques, which are often above 500 °C . Indeed, the high quality polycrystalline ZnO films have been deposited by ALD at temperatures as low as 100 °C. , …”

Section: Introductionmentioning

confidence: 99%

Role of Hydrogen-Related Defects in Photocatalytic Activity of ZnO Films Grown by Atomic Layer Deposition

et al. 2020

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The photocatalytic activity of ZnO films, grown by atomic layer deposition on sapphire, was investigated for different amounts of residual hydrogen incorporated unintentionally into the matrix during the crystal growth. A close correlation was found between the level of incorporated hydrogen and the rate of photocatalytic degradation of methylene blue on ZnO films. The rate of degradation is consistent with predominantly zero-order reaction kinetics. An enhanced photocatalytic activity, observed for films of predominantly (001)-oriented grains and low concentration of residual hydrogen, is explained by the reduced number of hydrogen-related defects responsible for recombination of charge carriers in combination with the preferential adsorption of water on polar (001) surfaces of ZnO grains.

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“…There have been a few reports on conductive epitaxial ZnO layers doped with Ga or Al [18,19]. The growth of ALD deposited monocrystalline layers has been proved to be possible as well [20][21][22][23], but the conductivity of these layers has not been examined.…”

Section: Introductionmentioning

confidence: 99%

Highly conductive epitaxial ZnO layers deposited by atomic layer deposition

et al. 2014

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The possibility of depositing conductive epitaxial layers with atomic layer deposition has been examined. Epitaxial ZnO layers were grown on GaN and doped with Al. The resistivity of the epitaxial layers is between 0.6 and 2*10 -4 Ωcm with both the mobilities and the carrier concentrations very high. The source of the high carrier concentration was found to be a combination of Al and Ga doping, the latter resulted by Ga atoms diffusing into the ZnO from the GaN substrate.

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Structure and stimulated emission of a high-quality zinc oxide epilayer grown by atomic layer deposition on the sapphire substrate

Cited by 20 publications

References 40 publications

Growth morphology and electrical/optical properties of Al-doped ZnO thin films grown by atomic layer deposition

Growth morphology and electrical/optical properties of Al-doped ZnO thin films grown by atomic layer deposition

Role of Hydrogen-Related Defects in Photocatalytic Activity of ZnO Films Grown by Atomic Layer Deposition

Highly conductive epitaxial ZnO layers deposited by atomic layer deposition

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