ZnO – nanostructures, defects, and devices

Schmidt‐Mende, Lukas; MacManus‐Driscoll, Judith L.

doi:10.1016/s1369-7021(07)70078-0

Cited by 1,588 publications

(919 citation statements)

References 122 publications

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“…Here, the Zn 2+ species reacts with OH − to form the Zn(OH) 2 intermediate complex, which decomposes to ZnO at high temperatures. This can be demonstrated in the following chemical reactions [37]:…”

Section: Introductionmentioning

confidence: 93%

Ultraviolet Sensors Based on Two-Dimensional Zinc Oxide Structures

Al-Hardan¹,

Hamid²,

RoslindaShamsudin³

et al. 2017

Optoelectronics - Advanced Device Structures

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In this chapter, we review the application of zinc oxide (ZnO) in ultraviolet (UV) sensing and emphasise on the two-dimensional (2D) ZnO structures. The synthesis of 2D ZnO structures, the morphologies, and the photoluminescence emission will be reviewed and highlighted. The performance of the UV sensors based on 2D ZnO structures is explored. The lack in the study of the 2D ZnO UV sensors might be due to the difficulties of controlling the growth of the 2D ZnO compared to the one-dimensional (1D) ZnO structures.

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Section: Introductionmentioning

confidence: 93%

Ultraviolet Sensors Based on Two-Dimensional Zinc Oxide Structures

Al-Hardan¹,

Hamid²,

RoslindaShamsudin³

et al. 2017

Optoelectronics - Advanced Device Structures

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“…ZnO has a wide direct energy band gap of 3.37 eV at room temperature (25 °C), many radiative deep level defects and relatively large exciton binding energy of 60 meV, which makes ZnO useful for sensing and optoelectronic device applications [44,45].…”

Section: Metal Oxide Semiconductor Nanostructuresmentioning

confidence: 99%

Synthesising Metal Oxide Materials and Their Composite Nanostructures for Sensing and Optoelectronic Device Applications

Khun¹

2015

Linköping Studies in Science and Technology. Dissertations

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Research on nanomaterials has been revolutionized in the last few years because of the attractive properties they have in comparison to the bulk phase of similar materials. These properties are physical, chemical, catalytic and optical. Among these nanomaterials, the metal oxide nanostructures have become of particular interest to scientists for the development of different optical, biochemical and biomedical nanodevices. In the present research work using the advantageous features of nanotechnology, high performance nanodevices for optoelectronics with a wide band gap compound nanostructure and highly sensitive sensor devices have been demonstrated. The nanotechnology is used to fabricate sensitive and precise nanodevices based on nanomaterials for the application of sensing.Among metal oxide nanostructures, ZnO, CuO and NiO are attractive materials because of their unique properties; their high surface area to volume ratio, their energy band gap of 3.37 eV, 1.2 eV and 3.7 eV, respectively, biocompatibility, high electron mobility, fast electron transfer rate and they are environmental-friendly in many applications. When used in sensor devices, nanomaterials have indicated high selectivity for possible use to detect the various analytes even in small volumes. Metal oxide nanostructures have shown to be good for optoelectronic nanodevices because of their electrical characteristics, high optical absorption and low-processing temperature.In this thesis, the synthesis of different morphologies of metal oxide semiconductor nanostructures and their composite using the hydrothermal method are demonstrated for various applications. This thesis is divided into three parts:In the first part of this research work, the fabrication of well-aligned ZnO nanorods using different concentrations of composite seed layer of inorganic and organic materials when using the hydrothermal growth method is presented. The effect of the composite seed layer on the i Abstract alignment, density and optical properties of the grown ZnO nanorods is investigated (paper I).Utilizing the advantage of ZnO nanostructure, a comparative study of ZnO nanorods and thin films for chemical and biosensing application was carried out. The ZnO nanorods and thin films were functionalized with strontium ionophore membrane, immobilized the galactose oxidase and lactate oxidase for determining the strontium ions, D-galactose and L-lactic acid, respectively (paper II).In the second part, the effects of different urea concentrations on the morphology of CuO nanostructures is studied as described in paper III. Moreover, CuO nanoflowers were functionalized with cadmium ion ionophore for the detection of Cd ions, while CuO nanosheets were grown by the low temperature growth method and were used for the development of a nonenzymatic glucose sensor, respectively (Paper IV).In the last part of this thesis, composite nanostructures of CuO/ZnO and NiO/ZnO were applied to develop dopamine sensor and fast sensitive UV photodetector, respectively. A nanohybrid of C...

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“…25,26 Note that the controllability of the defect density depends on the type of defect and the semiconductor itself. 1,6,[8][9][10][11][12][13] In the context of ZnO, numerous studies deal with V O s, 4,8,10,11,13,21 which is not the case with Zn i s. It is also notable that the balance between the relative densities of Zn i s and V O s is still challenging.…”

Section: Introductionmentioning

confidence: 99%

Role of zinc interstitials and oxygen vacancies of ZnO in photocatalysis: a bottom-up approach to control defect density

et al. 2014

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Oxygen vacancies (V O s) in ZnO are well-known to enhance photocatalytic activity (PCA) despite various other intrinsic crystal defects. In this study, we aim to elucidate the effect of zinc interstitials (Zn i ) and V O s on PCA, which has applied as well as fundamental interest. To achieve this, the major hurdle of fabricating ZnO with controlled defect density requires to be overcome, where it is acknowledged that defect level control in ZnO is significantly difficult. In the present context, we fabricated nanostructures and thoroughly characterized their morphological (SEM, TEM), structural (XRD, TEM), chemical (XPS) and optical (photoluminescence, PL) properties. To fabricate the nanostructures, we adopted atomic layer deposition (ALD), which is a powerful bottom-up approach. However, to control defects, we chose polysulfone electrospun nanofibers as a substrate on which the non-uniform adsorption of ALD precursors is inevitable because of the differences in the hydrophilic nature of the functional groups. For the first 100 cycles, Zn i s were predominant in ZnO quantum dots (QDs), while the presence of V O s was negligible. As the ALD cycle number increased, V O s were introduced, whereas the density of Zn i remained unchanged. We employed PL spectra to identify and quantify the density of each defect for all the samples. PCA was performed on all the samples, and the percent change in the decay constant for each sample was juxtaposed with the relative densities of Zn i s and V O s. A logical comparison of the relative defect densities of Zn i s and V O s suggested that the former are less efficient than the latter because of the differences in the intrinsic nature and the physical accessibility of the defects. Other reasons for the efficiency differences were elaborated.

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ZnO – nanostructures, defects, and devices

Cited by 1,588 publications

References 122 publications

Ultraviolet Sensors Based on Two-Dimensional Zinc Oxide Structures

Ultraviolet Sensors Based on Two-Dimensional Zinc Oxide Structures

Synthesising Metal Oxide Materials and Their Composite Nanostructures for Sensing and Optoelectronic Device Applications

Role of zinc interstitials and oxygen vacancies of ZnO in photocatalysis: a bottom-up approach to control defect density

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