Fractal characterization of the silicon surfaces produced by ion beam irradiation of varying fluences

Yadav, R. P.; Kumar, Tanuj; Mittal, Ashok; Dwivedi, Suneet; Kanjilal, D.

doi:10.1016/j.apsusc.2015.04.150

Cited by 44 publications

(21 citation statements)

References 43 publications

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“…The estimated values of ε for all the samples in present study lie between 0 to 1 indicating the formation of self‐affine surface. It is reported that the self‐affine surface behaves like a fractal . The fractal dimension ( D f ) can be calculated from ε by the relation D f = 3 − ε .…”

Section: Resultsmentioning

confidence: 99%

Effect of 120 MeV Au⁹⁺ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction

Das

Biswal

Choudhary

et al. 2018

Surface & Interface Analysis

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ZnO/NiO thin films, each of thickness 100 nm, were deposited on Si(100) substrate by pulsed laser deposition method. The resulting heterojunction, ZnO/NiO/Si, was irradiated by 120 MeV Au 9+ ions and characterized by grazing incidence X-ray diffraction (GIXRD), Raman spectroscopy, and atomic force microscopy (AFM). The GIXRD confirmed the presence of both NiO and ZnO in the samples. Ion irradiation induced suppression of crystalline nature, and the recrystallization of the same occurred at the fluence of 1 × 10 13 ions cm −2 . The occurrence of most intense band at 302 cm −1 in Raman spectra corresponds to the symmetric stretching vibration of ZnO. The linear shift of stretching mode of ZnO with ion fluence could be associated with the effect of compressive stress in the material. AFM analysis of the films indicated that the rms roughness increased when the film is irradiated at a fluence of 1 × 10 12 ions cm −2 .Beyond this fluence, the value of roughness decreased up to fluence of 1 × 10 13 ions cm −2 and increased thereafter. To see the effect of the stress of buffer layer on the surface layer, we calculated the stress for NiO layer with ion fluence form the lattice parameter. Comparing the stress of buffer layer with roughness of surface layer at the given fluence, we can say that the compressive stress in the buffer layer could possibly control the roughness of the surface layer. KEYWORDS atomic force microscope, heterostructure, ion irradiation, stress 1 | INTRODUCTION Heterojunction devices, formed by combining semiconductors with different band gap and closely matching lattice parameters, have attracted much attention in optoelectronics. 1 ZnO is a wide-band gap (3.37 eV) semiconductor of the II-VI group. 2 It exhibits intrinsic n-type semiconducting property due to oxygen vacancies and zinc interstitials. It exhibits several properties like large exciton binding energy, 3 good transparency, 4 high electron mobility, 5 high thermal conductivity, 6 and strong room-temperature luminescence 7 for various device applications like liquid crystal displays, transparent conducting electrodes in solar cells, light emitting diodes, thin film transistors, gas sensors, and spintronic applications. 8 NiO is another wide band gap semiconductor that shows p-type behaviour due to the vacancy at Ni 2+ sites. NiO is widely used for applications such as transparent conductive films, 9 anode material, 10 and electrochromic devices. 11 Heterojunctions formed out of two layers (n-type ZnO and p-type NiO) can exhibit the potential of both the materials, in addition to the junction characteristics. In 2003, Ohta et al., 12 first reported the preparation of transparent NiO/ZnO heterojunction by pulsed laser deposition (PLD) combined with a solid-phase-epitaxy technique. Since then, many developments have been reported on the preparation and application of this heterojunction. These include methods like sol-gel spin coating, 13 chemical bath deposition, 4 hydrothermal method, 14and PLD. 15 On the application front, use of the hete...

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Section: Resultsmentioning

confidence: 99%

Effect of 120 MeV Au⁹⁺ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction

Das

Biswal

Choudhary

et al. 2018

Surface & Interface Analysis

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“…The another parameter interface width is the root mean square (rms) deviation of surface height from the mean, computed by

w = \frac{1}{N} \sqrt{\sum_{i = 1}^{N} \sum_{j = 1}^{N} {[z (i, j) - 〈z (i, j)〉]}^{2}}

…”

Section: Methodsmentioning

confidence: 99%

“…Fractal analysis is a powerful analytical tool which can extract information of the surface that can not be extracted from traditional analysis . The most important characteristics of fractal is its dimension which describes how some property changes with scale at which it is measured . Interface width and average surface roughness measure the global variation of roughness and fail to explain the local variation of roughness.…”

Section: Introductionmentioning

confidence: 99%

“…26 The turning point of the curves determine the value of lateral correlation length ζ and can be obtained as the value of r, at which H(r) increases to the value 2w 2 {(1 − (1/e))}.The lateral correlation lengths of the irradiated surface are found to be 0.22, 0.50, 1.20, and, 1.37 nm for the energy of 35, 50, 75, and 100 keV, respectively. The increasing value of ζ shows that the heights at the two surface points within ζ are considered as more correlated at higher energy 18. The slope of the straight line at a smaller r value gives the roughness exponent (α) corresponding to each ion irradiated surface.…”

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Fractal characterizations of energetic Si ions irradiated amorphized‐Si surfaces

Maity

Ojha

Sulania

et al. 2019

Surface & Interface Analysis

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The fractal characterizations of amorphized‐silicon (a‐Si) surfaces under low‐energy ion irradiations are presented. The crystalline Si surfaces have been irradiated with Si ions having different energy of 35, 50, 75, and 100 keV at a fixed fluence of 2 × 1015 ions‐cm−2. The samples have been characterized by means of using Raman spectroscopy, Channeling‐Rutherford backscattering spectrometry (C‐RBS), and atomic force microscopy (AFM) techniques. The ion irradiation leads to the amorphization of Si near surface and subsurface region, as confirmed by Raman and C‐RBS measurement. The AFM analysis shows that the ion irradiation also leads to the formation of nanodots on the surface and size of the dots increases with increasing of the ion energy. The fractal analysis has been performed using AFM images in order to get the significant evidence about nanodot formations and the correlation inside the surface microstructures. The kinetic roughening and surface smoothening, due to dissipation of kinetic energy of ions through collision cascades of the surface atoms, lead to the formation of dot‐like structures.

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“…Among the various surface patterning techniques, ion-beam irradiation of the solid surface is considered a very effective approach to the generation of self-organized nanostructures and ripple patterns [8][9][10][11][12][13][14]. Apart that, ion beams of higher energies (for example swift heavy ion beams), can be used as/in phase transformations [15] and surface restructuring [16,17].…”

Section: Introductionmentioning

confidence: 99%

Energy-separated sequential irradiation for ripple pattern tailoring on silicon surfaces

Kumar

Panchal

et al. 2015

Applied Surface Science

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Fractal characterization of the silicon surfaces produced by ion beam irradiation of varying fluences

Cited by 44 publications

References 43 publications

Effect of 120 MeV Au⁹⁺ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction

Effect of 120 MeV Au⁹⁺ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction

Fractal characterizations of energetic Si ions irradiated amorphized‐Si surfaces

Energy-separated sequential irradiation for ripple pattern tailoring on silicon surfaces

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Fractal characterization of the silicon surfaces produced by ion beam irradiation of varying fluences

Cited by 44 publications

References 43 publications

Effect of 120 MeV Au9+ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction

Effect of 120 MeV Au9+ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction

Fractal characterizations of energetic Si ions irradiated amorphized‐Si surfaces

Energy-separated sequential irradiation for ripple pattern tailoring on silicon surfaces

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Effect of 120 MeV Au⁹⁺ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction

Effect of 120 MeV Au⁹⁺ ion irradiation on the structure and surface morphology of ZnO/NiO heterojunction