Photoinduced Formation of Zinc Nanoparticles by UV Laser Irradiation of ZnO

Khan, Enamul; Langford, S. C.; Dickinson, J. T.; Boatner, L. A.; Hess, Wayne P.

doi:10.1021/la804143u

Cited by 33 publications

(20 citation statements)

References 33 publications

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“…With sufficient number of V O s it turns to be dark reddish brown that appears as black. However, a recent investigation shows 37 the appearance of black colour in ZnO with laser irradiation. It has been observed 37 that segregation of metallic zinc has taken place in the irradiated region.…”

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confidence: 98%

Interplay of defects in 1.2 MeV Ar irradiated ZnO

Chattopadhyay

Dutta

Jana

et al. 2010

Journal of Applied Physics

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Defect characterization in 1.2 MeV Ar8+ irradiated polycrystalline ZnO has been carried out by x-ray diffraction (XRD), scanning electron microscopy (SEM) along with electrical resistivity, and photoluminescence (PL) measurements at room temperature (RT). Interestingly, irradiation with the initial fluence (1×1015 ions/cm2) changes the color of the sample from white to orange while the highest irradiation fluence (5×1016 ions/cm2) makes it dark reddish brown that appears as black. XRD study reveals no significant change in the average grain size of the samples with irradiation fluence. Increase in surface roughness due to sputtering is clearly visible in SEM with highest fluence of irradiation. RT PL spectrum of the unirradiated sample shows intense ultraviolet (UV) emission (∼3.27 eV) and less prominent defect level emissions (2–3 eV). The overall emission is largely quenched due to initial irradiation fluence. Increasing the fluence of Ar beam further, UV emission is enhanced along with prominent defect level emissions. Remarkably, the resistivity of the irradiated sample with highest fluence is reduced by four orders of magnitude compared to that of the unirradiated sample. This is due to an increase in donor concentration as well as their mobility induced by high fluence of irradiation. Change in color in the irradiated samples indicates dominant presence of oxygen vacancies. It is now well known that oxygen vacancies are deep donors in ZnO. So oxygen vacancies, in principle, are not the source of conductivity in ZnO at RT. Simultaneous evolution of coloration and conductivity in ZnO, as is seen in this study, indicate that oxygen vacancies strongly influence the stability of shallow donors, presumably zinc interstitial related (highly mobile Zn interstitials also need to form defect pair/complex to be stable), which act as major source of carriers. Such a contention is in conformity with most recent theoretical calculations.

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mentioning

confidence: 98%

Interplay of defects in 1.2 MeV Ar irradiated ZnO

Chattopadhyay

Dutta

Jana

et al. 2010

Journal of Applied Physics

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“…12 At somewhat higher fluences (250-400 mJ/cm 2 ), we observe evidence for the accumulation of surface metallic zinc as nanoparticles. 33 Below we describe sustained Zn þ emission at fluences above 160 mJ/cm 2 , consistent with continuous photodecomposition. We therefore suggest that the transient photodecomposition during the first few laser pulses is limited by a relatively uniform, zinc-rich layer on or near the surface.…”

Section: Intensity Versus Pulse Numbermentioning

confidence: 56%

“…At these same fluences, we also detect sustained neutral emission (e.g., neutral Zn and atomic O). 37 The onset of detectable Zn emission occurs at a fluence near 160 mJ/cm 2 , and its intensity increases in proportion to $F 8 , where F is the fluence. The kinetic energies of this Zn emission range from near 0 to 2-4 eV.…”

Section: F Atomic Zinc Ions At Higher Fluencesmentioning

confidence: 99%

“…4), DT % 300 K. Significantly higher temperatures (near the boiling point of metallic zinc) are required to remove any zinc which might accumulate at the surface. 33 Thus it is reasonable to suppose that, over a few laser pulses, the surface becomes oxygen deficient or zinc rich, and that decomposition ceases. The resulting surface would be characterized by zinc vacancies and adions (in addition to adsorbed neutral zinc) as well as a small number of oxygen vacancies.…”

Section: Intensity Versus Pulse Numbermentioning

confidence: 99%

“…38,39 (Further evidence of 193 nm excitation of Zn into this autoionization state will be provided in manuscripts currently in preparation. 40 ) Varoucha et al have determined the two-photon cross section for the ionization of zinc atoms by 6.4 eV photons to be $1 Â 10 À48 cm 4 s À1 . 41 At a fluence of 500 mJ/cm 2 , the average photon flux in a 20 ns pulse is 2:5 Â 10 25 photons Á cm À2 s À1 , which yields an ionization probability of 1 Â 10 À5 .…”

Section: F Atomic Zinc Ions At Higher Fluencesmentioning

confidence: 99%

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The interaction of 193-nm excimer laser irradiation with single-crystal zinc oxide: Positive ion emission

Khan

Langford

Dickinson

et al. 2012

Journal of Applied Physics

Self Cite

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We examine UV laser-induced ion emission from a wide bandgap semiconductor, single-crystal ZnO, at fluences well below both the damage threshold and plasma formation. At fluences below 200 mJ/cm2, we observe only Zn+, and the Zn+ intensity decreases monotonically during exposure. At higher fluences, after an initial decrease, the emission is sustained; in addition O+ and O2+ are observed. We explain: how Zn ions of several eV in energy can be produced on the surface of a semiconductor, how sustained emission can be maintained, and the origin of an anomalous emission of slow Zn+ ions — the latter is shown to arise from photoionization of atomic Zn, also emitted by this radiation.

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Recent Progress in Photonic Processing of Metal‐Oxide Transistors

Yarali

Koutsiaki

Faber

et al. 2019

Adv Funct Materials

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(1 of 37)high mobility (µ) (even in amorphous phase), wide bandgap (transparent in the visible range), and the ability to be controllably doped. Importantly, they can be grown into thin films and various nanostructures with different scalable deposition techniques, including vacuum-based methods such as physical vapor deposition (PVD) [7,8] and chemical vapor deposition (CVD) [9] as well as solution-based processes such as spray [10] and spin coating. [11] Moreover, the resulting layers can be easily patterned using standard fabrication procedures and as such can be integrated into state-of-the-art processes for (opto)electronic applications. The above-mentioned capabilities have led to a plethora of applications such as switching backplanes for displays, transparent and flexible electronics, integrated circuits (ICs), photovoltaics (PVs), organic light-emitting diodes (OLEDs), capacitors, batteries, photocatalytic devices, electrochromics and memory devices, to name but a few. [8,[12][13][14] Because of their ability to be doped, their electronic properties can be tuned from dielectrics to semiconductors and conductors. This characteristic versatility has recently been exploited to stretch the range of their applications to new technological sectors, such as plasmonics in the near infrared and midinfrared spectral ranges. [12,15] One of the driving applications of metal oxides is in thinfilm transistors (TFTs) for large area electronics such as current driven optical displays and ICs. Following the early demonstrations, [16] most effort focused on the fabrication and processing of metal oxides TFTs paying particular attention to the device performance and applications. [1,5,6,17] Especially when processed over large areas, as in the case for display applications, the complexity to precisely control the device reliability and reproducibility becomes a challenging aspect of any TFT technology. To that respect, solution-based techniques progressed rapidly due to their lower cost and higher throughput compared to vacuum-based techniques. In both cases, the metal-oxide deposition has so far been limited to high processing temperatures (>250 °C) (Figure 1a) which renders the technology incompatible with inexpensive, temperature-sensitive substrates such as polymers, the material class of choice for various high throughput manufacturing techniques such as roll-to-roll (R2R) and sheet-to-sheet (S2S)Over the past few decades, significant progress has been made in the field of photonic processing of electronic materials using a variety of light sources. Several of these technologies have now been exploited in conjunction with emerging electronic materials as alternatives to conventional hightemperature thermal annealing, offering rapid manufacturing times and compatibility with temperature-sensitive substrate materials among other potential advantages. Herein, recent advances in photonic processing paradigms of metal-oxide thin-film transistors (TFTs) are presented with particular emphasis on the use of various light sour...

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Photoinduced Formation of Zinc Nanoparticles by UV Laser Irradiation of ZnO

Cited by 33 publications

References 33 publications

Interplay of defects in 1.2 MeV Ar irradiated ZnO

Interplay of defects in 1.2 MeV Ar irradiated ZnO

The interaction of 193-nm excimer laser irradiation with single-crystal zinc oxide: Positive ion emission

Recent Progress in Photonic Processing of Metal‐Oxide Transistors

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