Weakening of excitonic screening effects in Ti Zn1-O thin films

Nurfani, Eka; Satrya, Christoforus Dimas; Abdurrahman, Irfan; Sutjahja, Inge Magdalena; Winata, Toto; Takase, Kouichi; Rusydi, Andrivo; Darma, Yudi

doi:10.1016/j.tsf.2017.11.015

Cited by 13 publications

(3 citation statements)

References 47 publications

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“…[37] To acquire optical parameters successfully for the ionimplanted layer, the measured spectra are parameterized by using Tauc-Lorentz oscillators. [38] The Tauc-Lorentz oscillator is defined by [ε 1 (∞), A, C, E g , and E n0 ], and they involve the effects of high energy, amplitude parameter, a broadening parameter, bandgap energy, and peak transition energy, respectively. The TL dispersion mode gives the expression of the dielectric function as shown below: [39]…”

Section: Resultsmentioning

confidence: 99%

Analysis of properties of krypton ion-implanted Zn-polar ZnO thin films*

Jiang¹,

Lian²,

Ying³

et al. 2021

Chinese Phys. B

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The optical properties of materials are of great significance for their device applications. Different numbers of krypton ions are doped into high-quality Zn-polar ZnO films fabricated by molecular beam epitaxy (MBE) on sapphire substrates through ion implantation. Krypton is chemically inert. The structures, morphologies, and optical properties of films are measured. The x-ray diffraction (XRD) spectra confirm the wurtzite structures of Zn-polar ZnO films. Atomic force microscopy (AFM) results show that the films have pit surface structure and higher roughness after Kr ion implantation. A detailed investigation of the optical properties is performed by using the absorption spectrum, photoluminescence (PL), and spectroscopic ellipsometry (SE). The absorption spectrum is measured by UV-visible spectrophotometer and the bandgap energy is estimated by the Tauc method. The results show that the absorption increases and the bandgap decreases after Kr ion implantation. Moreover, the Kr ion implantation concentration also affects the properties of the film. The ellipsometry results show that the films’ refractive index decreases with the Kr ion implantation concentration increasing. These results can conduce to the design and optimization of Kr ion-implanted polar ZnO films for optoelectronic applications.

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Section: Resultsmentioning

confidence: 99%

Analysis of properties of krypton ion-implanted Zn-polar ZnO thin films*

Jiang¹,

Lian²,

Ying³

et al. 2021

Chinese Phys. B

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“…When a photon has enough energy, an electron is excited from the O-2p valence band to the Zn-3d conduction band. For ZnO-3 and ZnO-4, there is strong absorption around 3 eV, which may be correlated to defect-induced optical absorption [48,49]. Furthermore, optical band gap values are analyzed using the Tauc-plot method, as shown in figure 4.…”

Section: Optical Propertiesmentioning

confidence: 99%

Seedless hydrothermal growth of hexagonal prism ZnO for photocatalytic degradation of methylene blue: the effect of pH and post-annealing treatment

Oktapia,

Nurfani,

Wahjoedi

et al. 2023

Semicond. Sci. Technol.

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In this paper, we study the effect of solution pH in the hydrothermal synthesis and post-annealing treatment on the photocatalytic performance of hexagonal prism ZnO grown without a seed layer. By varying the precursor molarity ratio, the solution obtained was 6.88 (ZnO-2), 7.00 (ZnO-1), and 7.58 (ZnO-3). The three samples show hexagonal prism ZnO with wurtzite structures based on scanning electron microscope and x-ray diffraction analysis. ZnO-1 samples could degrade methylene blue as high as 65.9% for a UV irradiation time of 5 hours, better than ZnO-2 (51.80%) and ZnO-3 (57.55%). Post-annealing treatment of ZnO-1 with the best photodegradation efficiency was carried out at 200°C (ZnO-4) and 400°C (ZnO-5) to alter the structure. The post-annealing treatment changes the domination of crystal orientation from (002) to (100) plane. Also, the morphology of ZnO-5 changed significantly to become smaller rods with a diameter of 2.79 µm, as compared to ZnO-1 (2.83 µm) and ZnO-4 (3.12 µm). It is due to ionic rearrangements occurring at higher temperatures. The ZnO-5 sample reduces methylene blue by 82.91%, which is better than ZnO-1 (65.9%) and ZnO-4 (64.39%). Interestingly, we found a relation between smaller rod diameters and higher photocatalytic activity. The results show the importance of the solution pH and the annealing treatment in improving the photocatalytic performance of hexagonal prism ZnO without the seed layer.

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“…Zinc oxide has become one of the most influential materials in the wide range of applications and current technology developments due to its abundance, and simple fabrication process. Other superiorities such as having 3.37 eV direct band gap and 60 meV exciton binding energy at room temperature make ZnO feasible for efficient‐optical applications such as UV emitter and semiconductor laser . As material with high transparency up to 97%, ZnO with Ga dopant can be utilized to produce UV and blue LED with high efficiency …”

Section: Introductionmentioning

confidence: 99%

Room Temperature Strong Emission and Excitonic Enhancement in Multiple‐Stacked Nano‐Porous ZnO Thin Film

Darma

Chichvarina²,

Purbayanto

et al. 2018

Physica Status Solidi (a)

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Electronic and structural properties of ZnO films before and after H 2 annealing treatment are studied. The initial system is smooth amorphous ZnO films that are intentionally grown at room temperature. A dramatic change is found in the crystallinity and the surface transforms to a multiple-stacked nanoporous structure upon annealing as observed by scanning electron microscopy and X-ray diffraction. Photoluminescence spectroscopy shows the presence of a new mid-gap state below the first optical transition, and the annealing treatment transforms the ZnO system to more transparent film. Interestingly, it is found that the structural evolution changes the dielectric function measured by high-resolution, angle-dependent spectroscopic ellipsometry and this generates strong emission at %2.5 eV. These results show the importance of structural modification via H 2 annealing to control the optical properties and electronic structure of ZnO films.

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Weakening of excitonic screening effects in Ti Zn1-O thin films

Cited by 13 publications

References 47 publications

Analysis of properties of krypton ion-implanted Zn-polar ZnO thin films*

Analysis of properties of krypton ion-implanted Zn-polar ZnO thin films*

Seedless hydrothermal growth of hexagonal prism ZnO for photocatalytic degradation of methylene blue: the effect of pH and post-annealing treatment

Room Temperature Strong Emission and Excitonic Enhancement in Multiple‐Stacked Nano‐Porous ZnO Thin Film

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