Synthesis and characterization of Cu-doped ZnO nanorods chemically grown on flexible substrate

Shabannia, R.

doi:10.1016/j.molstruc.2016.04.015

Cited by 33 publications

(10 citation statements)

References 24 publications

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“…Consequently, the surface depletion region at the NR surface is expanded. When the TM-dopants are introduced into ZnO nanocrystals, they can drop the electron concentration n (see our Hall measurements in Table 3 ) due to the reduction of intrinsic defects, such as O v and Zn i , as revealed by our PL and XPS analysis and other recent reports [ 18 , 54 ].…”

Section: Resultssupporting

confidence: 73%

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate

Ajmal¹,

Khan²,

Nam³

et al. 2020

Nanomaterials

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A growth scheme at a low processing temperature for high crystalline-quality of ZnO nanostructures can be a prime stepping stone for the future of various optoelectronic devices manufactured on transparent plastic substrates. In this study, ZnO nanorods (NRs) grown by the hydrothermal method at 150 °C through doping of transition metals (TMs), such as Co, Ni, or Co-plus-Ni, on polyethylene terephthalate substrates were investigated by various surface analysis methods. The TM dopants in ZnO NRs suppressed the density of various native defect-states as revealed by our photoluminescence and X-ray photoelectron spectroscopy analysis. Further investigation also showed the doping into ZnO NRs brought about a clear improvement in carrier mobility from 0.81 to 3.95 cm2/V-s as well as significant recovery in stoichiometric contents of oxygen. Ultra-violet photodetectors fabricated with Co-plus-Ni codoped NRs grown on an interdigitated electrode structure exhibited a high spectral response of ~137 A/W, on/off current ratio of ~135, and an improvement in transient response speed with rise-up and fall-down times of ~2.2 and ~3.1 s, respectively.

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Section: Resultssupporting

confidence: 73%

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate

Ajmal¹,

Khan²,

Nam³

et al. 2020

Nanomaterials

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“…When Cu and/or Ni dopants are introduced, they tend to drop the free electron concentration, n, in the conduction band because of the reduced oxygen vacancies in the ZnO nanorod crystal as shown in our results of PL and XPS analysis and also in the report of R . Shabannia [24]. The surface depletion layer thickness, δ of the nanorods is given by [9]: δ=LD(eVskT)1/2 LD=(εokTe2n)1/2 where L D is the Debye length, V S is the adsorbate-induced band bending, e is the electron charge, kT is the thermal energy, and ε o is the permittivity.…”

Section: Resultsmentioning

confidence: 99%

“…Among the various transition metals, Cu dopants are especially interesting because of their electronic shell structure is comparable to the chemical and physical properties of Zn. Cu impurities can improve the crystallinity of ZnO nanorods by suppressing the defects related to oxygen or zinc vacancies [24]. However, Ni dopants also have the advantage of the fair solubility of Ni 2+ ions in ZnO tetrahedral coordinates because their ionic radius is comparable to that of Zn 2+ [25,26].…”

Section: Introductionmentioning

confidence: 99%

High-Performance Flexible Ultraviolet Photodetectors with Ni/Cu-Codoped ZnO Nanorods Grown on PET Substrates

et al. 2019

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As a developing technology for flexible electronic device fabrication, ultra-violet (UV) photodetectors (PDs) based on a ZnO nanostructure are an effective approach for large-area integration of sensors on nonconventional substrates, such as plastic or paper. However, photoconductive ZnO nanorods grown on flexible substrates have slow responses or recovery as well as low spectral responsivity R because of the native defects and inferior crystallinity of hydrothermally grown ZnO nanorods at low temperatures. In this study, ZnO nanorod crystallites are doped with Cu or Ni/Cu when grown on polyethylene terephthalate (PET) substrates in an attempt to improve the performance of flexible PDs. The doping with Ni/Cu or Cu not only improves the crystalline quality but also significantly suppresses the density of deep-level emission defects in as-grown ZnO nanorods, as demonstrated by X-ray diffraction and photoluminescence. Furthermore, the X-ray photoelectron spectroscopy analysis shows that doping with the transition metals significantly increases the oxygen bonding with metal ions with enhanced O/Zn stoichiometry in as-grown nanorods. The fabricated flexible PD devices based on an interdigitated electrode structure demonstrates a very high R of ~123 A/W, a high on-off current ratio of ~130, and a significant improvement in transient response speed exhibiting rise and fall time of ~8 and ~3 s, respectively, by using the ZnO nanorods codoped by Ni/Cu.

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“…[22][23][24][25][26][27] Other investigations have reported the use of copper chloride, copper acetate, and copper sulfate. [28][29][30] However, the required conditions in the chemical bath for inducing the Cu incorporation and the nature of the related mechanisms have not been described in detail. Surprisingly, the influence of the pH in the chemical bath has typically not been considered thoroughly.…”

Section: Introductionmentioning

confidence: 99%

Chemical Bath Deposition of ZnO Nanowires Using Copper Nitrate as an Additive for Compensating Doping

et al. 2021

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The controlled incorporation of dopants like copper into ZnO nanowires (NWs) grown by chemical bath deposition (CBD) is still challenging despite its critical importance for the development of piezoelectric devices. In this context, the effects of the addition of copper nitrate during the CBD of ZnO NWs grown on Au seed layers are investigated in detail, where zinc nitrate and hexamethylenetetramine are used as standard chemical precursors and ammonia as an additive to tune the pH. By combining thermodynamic simulations with chemical and structural analyses, we show that copper oxide nanocrystals simultaneously form with ZnO NWs during the CBD process in the low-pH region associated with a large supersaturation of Cu species. The Cu(II) and Zn(II) speciation diagrams reveal that both species show very similar behaviors, as they predominantly form either X 2+ ions (with X = Cu or Zn) or X(NH3)4 2+ ion complexes, depending on the pH value. Owing to their similar ionic structures, Cu 2+ and Cu(NH 3 ) 4 2+ ions preferentially formed in the low-and high-pH regions, respectively, are able to compete with the corresponding Zn 2+ and Zn(NH3)4 2+ ions to adsorb on the c-plane top facets of ZnO NWs despite repulsive electrostatic interactions, yielding the significant incorporation of Cu. At the highest pH value, additional attractive electrostatic interactions between the Cu(NH 3 ) 4 2+ ion complexes and negatively charged c-plane top facets further

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Synthesis and characterization of Cu-doped ZnO nanorods chemically grown on flexible substrate

Cited by 33 publications

References 24 publications

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate

High-Performance Flexible Ultraviolet Photodetectors with Ni/Cu-Codoped ZnO Nanorods Grown on PET Substrates

Chemical Bath Deposition of ZnO Nanowires Using Copper Nitrate as an Additive for Compensating Doping

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