Hole traps and Cu-related shallow donors in ZnO nanorods revealed by temperature-dependent photoluminescence

He, Haiping; Li, Shuili; Sun, Luwei; Ye, Zhizhen

doi:10.1039/c3cp50764e

Cited by 7 publications

(2 citation statements)

References 24 publications

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“…In addition, although it is well-known that the presence of lattice defects plays a key role in the physical and chemical properties of ZnO nanostructures, 10,11 many questions still remain due to the lack of conclusive evidence for defects responsible for luminescence properties. 13 In recent years, microwave-assisted chemistry is emerging as a powerful and innovative tool in all areas of synthetic chemistry due to its advantages over other synthetic methods, [14][15][16] such as shortened reaction times, cost-effectiveness, and cleaner reactions compared to conventional routes. 16,17 In particular, Kappe et al 18 reported a critical assessment of the specic role of microwave irradiation in the synthesis of ZnO micro-and nanostructured materials.…”

Section: Introductionmentioning

confidence: 99%

Correlation between structural and electronic order–disorder effects and optical properties in ZnO nanocrystals

et al. 2014

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The correlation between structural and electronic order-disorder effects in understanding the optical properties of flower-like ZnO nanocrystals synthesized by the microwave-assisted hydrothermal method at low temperatures and short times is discussed. Theoretical simulations were performed at the density functional theory level to gain a better understanding of the experimental data from X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), electron paramagnetic resonance (EPR), ultraviolet-visible diffuse reflectance (UV-vis) spectroscopy and photoluminescence (PL) measurement studies at different temperatures. The decrease in band gap values is due to the presence of intermediate states above the conduction band. These discrete levels are formed by structural and electronic disorder of tetrahedral [ZnO 4 ] clusters which enhance the electron-hole pair.

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Section: Introductionmentioning

confidence: 99%

Correlation between structural and electronic order–disorder effects and optical properties in ZnO nanocrystals

et al. 2014

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“…A small number of Cu + cations occupy positions in the interstices of the crystal lattice, playing the role of donor impurities with activation energy of 109 meV. The Cu 2+ state is 200 meV lower the bottom energy of the conduction band [22].…”

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confidence: 99%

Development of a Physical Model of Thermovoltaic Effects in the Thin Films of Zinc Oxide Doped with Transition Metals

et al. 2018

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A model of the thermovoltaic effect emergence in ZnO/ZnO (Me = Cu, Fe), sandwich structures has been developed in the article. The samples were made by the sol-gel method. When they were uniformly heated in a laboratory furnace in the temperature range of 200–300 °C, there an electromotive force (EMF) of −7~10 mV, not associated with the Seebeck effect, emerged. The developed physical mechanisms of the effect emergence consist of the following well-known fact: iron and copper coexist in zinc oxide in two states, namely, Fe2+ and Fe3+ (donor), and Cu2+ and Cu+ (acceptor). During the heating of the ZnO/ZnO–Me system, the concentration of charge carriers in the layers will increase, while in the upper layer its value will be larger because of the presence of electrically active impurities. At room temperatures, Coulomb forces retain an electron that is located on the Fe2+ ion, as well as a hole on Cu2+ ion, and the main states undergo ionization. However, as the temperature increases, the carrier concentration can reach a critical level, when they can screen the ion charge (the Debye screening radius decreases to the Bohr radius of the impurity). In this case, an abrupt collective endothermic process of ionization of multivalent impurities takes place, accompanied by the appearance of a concentration gradient of free carriers in the sample, and accordingly, the emergence of an electromotive force. Quantitative calculations of the critical temperature, at which the onset of EMF generation is observed, performed within the framework of the developed models.

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Annealing-induced changes of the 3.31 eV emission in ZnO nanorods

Sun

et al. 2013

Appl. Phys. A

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Hole traps and Cu-related shallow donors in ZnO nanorods revealed by temperature-dependent photoluminescence

Cited by 7 publications

References 24 publications

Correlation between structural and electronic order–disorder effects and optical properties in ZnO nanocrystals

Correlation between structural and electronic order–disorder effects and optical properties in ZnO nanocrystals

Development of a Physical Model of Thermovoltaic Effects in the Thin Films of Zinc Oxide Doped with Transition Metals

Annealing-induced changes of the 3.31 eV emission in ZnO nanorods

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