Changes in the electrical transport of ZnO under visible light

Dusari, S.; Barzola‐Quiquia, J.; Esquinazi, P.; Heluani, S. P.

doi:10.1016/j.ssc.2009.10.015

Cited by 6 publications

(2 citation statements)

References 13 publications

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“…A simple way to gain some information about the involved conduction mechanisms, is through the use of an indirect method, the complex impedance spectroscopy, which is a very well established method to investigate the transport mechanism in materials containing grains and interface contributions. In figure 7 we present the experimental data (Cole-Cole plot) at room temperature and in darkness in order to avoid influence of natural light containing an UV component [58]. We can recognize that the main arc is composed of three semi circles, indicating that the conduction mechanism in the nanowire consists of three capacitances.…”

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confidence: 99%

Electrical properties of ZnO single nanowires

et al. 2015

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We have investigated the electrical resistance R(T) of ZnO nanowires of ≈ 400 nm diameter as a function of temperature, between 30 K and 300 K, and frequency in the range 40 Hz to 30 MHz. The measurements were done on the as-prepared and after low-energy proton implantation at room temperature. The temperature dependence of the resistance of the wire, before proton implantation, can be well described by two processes in parallel. One process is the fluctuation induced tunneling conductance (FITC) and the other the usual thermally activated process. The existence of a tunneling conductance was also observed in the current-voltage ([Formula: see text]) results, and can be well described by the FITC model. Impedance spectroscopy measurements in the as-prepared state and at room temperature, indicate and support the idea of two contributions of these two transport processes in the nanowires. Electron backscatter diffraction confirms the existence of different crystalline regions. After the implantation of H(+) a third thermally activated process is found that can be explained by taking into account the impurity band splitting due to proton implantation.

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Section: » -+mentioning

confidence: 99%

Electrical properties of ZnO single nanowires

et al. 2015

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“…To investigate the influence of grains and grain boundaries contributions on the transport properties, we performed IS measures [36,37] in dark and at room temperature; this is necessary because ZnO is photoconductive in the near UV. [38] The results of the complex impedance are shown in Figure 3. The real and imaginary parts show two dominant contributions, obvious in the Cole-Cole plots, Figure 3c.…”

Section: Impedance Spectroscopymentioning

confidence: 99%

Magnetotransport Properties of Microstructured ZnO Thin Films Grown on a‐ and r‐Plane Sapphire Substrates

Barzola‐Quiquia¹,

Zelaya

Espíndola

et al. 2023

Physica Status Solidi (b)

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The transparent semiconductor ZnO has attracted substantial interest in the research community because of its potential applications as a transparent thin film, [1][2][3] transistor, [4][5][6] optoelectronic devices, [7][8][9] light-emitting diode, [10,11] among others. Another promising, non-inherent property is its roomtemperature ferromagnetism, which was first theoretically predicted to occur through doping with transition magnetic ions such as Fe, Co, or Ni. [12] However, many experimental studies revealed that the observed magnetic order is not related to the doping but certain defects. [13][14][15][16][17] A ferromagnetic ZnO, free of d-elements, opens new opportunities for applications in spintronics. The origin of the defect-induced magnetism (DIM) in defective ZnO samples is not always simple to explain, especially in samples where defects are introduced during the preparation of the samples, like Zn-or O-vacancies [15] or grain boundaries. [18] In these cases, the reproducibility of the magnetic order is low. Also, usual experimental techniques, such as SQUID (superconducting quantum interface device) magnetometry, cannot simply distinguish between defect-induced magnetic signals and those from other sources, like magnetic impurities on the samples or substrates. [19] However, recent theoretical and experimental studies using element-specific magnetic probes like X-ray magnetic circular dichroism (XMCD) in X-ray absorption spectroscopy [20] strongly suggest that Zn vacancies are the primary origin for the observed magnetic order in this compound. Oxygen vacancies, present in a more significant concentration than Zn vacancies, do not substantially contribute to the magnetic order due to their much smaller magnetic moment.Due to the low mass of thin films and weak magnetic signals (compared to the substrate), standard SQUID magnetometers are not the best choice for the magnetic characterization of ZnO thin films. Accounting for the influence of substrates by performing electrical transport measurements with an applied magnetic field is helpful. The measurement of the magnetoresistance (MR) and Hall effect (HE) [21] are powerful tools to explore the magnetic properties of conducting materials. In the case of MR, the sign of ferromagnetism is the opening of a butterfly-like hysteresis around zero field with extremes at fields corresponding to the coercive fields (H C ). When considering the HE, the appearance of an anomalous nonlinear contribution at low fields, in addition to the opening of a hysteresis with sign changes at fields corresponding to the coercive field, would be the case. We notice, however, that the field hysteresis depends on the coercive field of the investigated sample. Because H C is relatively weak in magnetic ZnO samples, that is, μ 0 Â H C ≤ 0.1 T, [15] high resolution is necessary to measure the hysteresis around zero field in the MR or HE. In general, with the field and temperature dependence of electrical-transport properties, it is possible to

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Synthesis and characterization of (Al, Co) co-doped ZnO for electronic applications

Ravindiran

Shankar

2016

J Mater Sci: Mater Electron

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Changes in the electrical transport of ZnO under visible light

Cited by 6 publications

References 13 publications

Electrical properties of ZnO single nanowires

Electrical properties of ZnO single nanowires

Magnetotransport Properties of Microstructured ZnO Thin Films Grown on a‐ and r‐Plane Sapphire Substrates

Synthesis and characterization of (Al, Co) co-doped ZnO for electronic applications

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