Control of electrical conductivity of highly stacked zinc oxide nanocrystals by ultraviolet treatment

Han, Wooje; Kim, Jiwan; Park, Hyung Ho

doi:10.1038/s41598-019-42102-3

Cited by 28 publications

(12 citation statements)

References 50 publications

(47 reference statements)

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“…The relative intensity of O p2 is critical to the electrical properties of ZnO thin films since high concentration of oxygen vacancies results in high electrical conductivity of those films, as will be exhibited later on. Finally, O p3 and O p4 at 532.22 and 533.14 eV are attributed to adsorbed oxy-hydroxide species and oxygen bonded to carbon, respectively. − …”

Section: Resultssupporting

confidence: 65%

Thermal Evaporation–Oxidation Deposited Aluminum Oxide as an Interfacial Modifier to Improve the Performance and Stability of Zinc Oxide-Based Planar Perovskite Solar Cells

Rodríguez-Castañeda

Moreno-Romero

Corpus-Mendoza

et al. 2020

ACS Appl. Energy Mater.

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The acid−base chemistry at the interface of zinc oxide (ZnO) and methylammonium lead tri-iodide (perovskite) leads to a proton transfer reaction that results in perovskite degradation. In perovskite solar cells (PSCs), this reaction produces low efficiency and reduces the long-term stability. In this work, an aluminum (Al) layer of 1−2 nm thickness is thermally evaporated on top of ZnO or Al 3+ -doped ZnO (ZnO:Al) thin films and then annealed at 450 °C for 30 min. Thermal annealing converts the surface aluminum film into a transparent and approximately 2 nm thick aluminum oxide (AlO x ) layer. Also, a larger concentration of oxygen vacancies is obtained by the annealing of Al and attributed to the diffusion of Al into the ZnO surface, and the ZnO underlayer results in a more conductive material. As a result, the chemical stability of perovskite coatings on top of AlO x -coated ZnO films is significantly enhanced, and the flat-band level of ZnO shifts 0.09 eV upwards, which improves the energetic level alignment in PSCs. This allows us to obtain ZnO:Al/AlO x -based planar PSCs that show a maximum efficiency of 16.56% with the perovskite layer prepared in ambient conditions under a relative humidity of 40−50%. After continuous illumination of about 30 min in air, ZnObased PSCs without AlO x layer retain only 34.5% of their original efficiency, whereas those with AlO x retain about 92.5%. It is demonstrated that thermal evaporation−oxidation is an efficient method to modify the surface properties of inorganic semiconductor thin films and improves both the performance and stability of PSCs.

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Section: Resultssupporting

confidence: 65%

Thermal Evaporation–Oxidation Deposited Aluminum Oxide as an Interfacial Modifier to Improve the Performance and Stability of Zinc Oxide-Based Planar Perovskite Solar Cells

Rodríguez-Castañeda

Moreno-Romero

Corpus-Mendoza

et al. 2020

ACS Appl. Energy Mater.

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“…In order to investigate the chemical states, the O 1s spectra of the samples with different annealing temperature (Figure 1c-h) are deconvoluted into two peaks, which are centered at 530.6 and 532.1 eV. In the literature, a peak at the lower binding energies of 530-531 eV is generally attributed to the O 2− binding at lattice points of ZnO, while the peak at the higher binding energies (531-532 eV) is ascribed to oxygen vacancies [32][33][34][35][36][37][38]. We thus assign the peaks at 530.…”

Section: Resultsmentioning

confidence: 88%

Air Annealing Effect on Oxygen Vacancy Defects in Al-doped ZnO Films Grown by High-Speed Atmospheric Atomic Layer Deposition

Hsu

Geng

et al. 2020

Molecules

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In this study, aluminum-doped zinc oxide (Al:ZnO) thin films were grown by high-speed atmospheric atomic layer deposition (AALD), and the effects of air annealing on film properties are investigated. The experimental results show that the thermal annealing can significantly reduce the amount of oxygen vacancies defects as evidenced by X-ray photoelectron spectroscopy spectra due to the in-diffusion of oxygen from air to the films. As shown by X-ray diffraction, the annealing repairs the crystalline structure and releases the stress. The absorption coefficient of the films increases with the annealing temperature due to the increased density. The annealing temperature reaching 600 °C leads to relatively significant changes in grain size and band gap. From the results of band gap and Hall-effect measurements, the annealing temperature lower than 600 °C reduces the oxygen vacancies defects acting as shallow donors, while it is suspected that the annealing temperature higher than 600 °C can further remove the oxygen defects introduced mid-gap states.

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“…Thermal annealing at 400 °C and higher temperature enhances the c -axis orientation of the films. , Raoufi and Raoufi reported that the grain size of ZnO thin films increased from 19 nm at 300 °C annealing to 28 nm at 500 °C annealing with a high light transmission exceeding 80% . Meanwhile, Han et al reported that nanostructured ZnO thin films that underwent ultraviolet treatments exhibited improved electrical properties owing to higher densification and the passivation of surface oxygen vacancies . Liu et al have grown a porous ZnO nanostructured film by the so-gel method using polyethylene glycol as the template as shown in Figure .…”

Section: Fabrication Methodsmentioning

confidence: 99%

Robust and Electrically Conductive ZnO Thin Films and Nanostructures: Their Applications in Thermally and Chemically Harsh Environments

Yan

Takahashi

Zeng

et al. 2021

ACS Appl. Electron. Mater.

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Harsh electronics", which are designed to operate under harsh environments, have garnered significant attention to collect various physical and chemical information in surroundings toward the Internet of Things era. Among various electronic materials and structures, ZnO thin films, which consist of an abundant resource, have been intensively investigated because of their unique electrical and optical properties. However, ZnO thin films have been regarded as chemically nonresistive to harsh environments (e.g., high temperatures, high humidity, and acidic and basic conditions). Herein, we present recent progress and advances in electrically conductive ZnO thin films and nanostructures for applications in harsh electronics. First, various fabrication methods and progresses for achieving high-quality ZnO nanomaterials are introduced. Subsequently, previously reported approaches for enhancing the reliability and stability of ZnO nanostructures in harsh electronics are compared. Strategies for fabricating robust ZnO materials and ZnO-based electronics are discussed on the basis of several proposed mechanisms. Finally, we describe the current limitation, perspective, and outlook for future developments of ZnO nanostructures for use in harsh electronics.

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Control of electrical conductivity of highly stacked zinc oxide nanocrystals by ultraviolet treatment

Cited by 28 publications

References 50 publications

Thermal Evaporation–Oxidation Deposited Aluminum Oxide as an Interfacial Modifier to Improve the Performance and Stability of Zinc Oxide-Based Planar Perovskite Solar Cells

Thermal Evaporation–Oxidation Deposited Aluminum Oxide as an Interfacial Modifier to Improve the Performance and Stability of Zinc Oxide-Based Planar Perovskite Solar Cells

Air Annealing Effect on Oxygen Vacancy Defects in Al-doped ZnO Films Grown by High-Speed Atmospheric Atomic Layer Deposition

Robust and Electrically Conductive ZnO Thin Films and Nanostructures: Their Applications in Thermally and Chemically Harsh Environments

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