Stable zinc-blende ZnO thin films: formation and physical properties

Chichvarina, Olga; Herng, T. S.; Phuah, Kia Chai; Xiao, Wen-Zhi; Bao, Nina; Feng, Ying; Ding, Jian-Hai

doi:10.1007/s10853-014-8561-0

Cited by 14 publications

(10 citation statements)

References 24 publications

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“…5 High-pressure zinc-blende or rock-salt phases were predicted by theory 6 and observed in experiment. [7][8][9] One of these non-equilibrium phases, the boron-nitride (BN) structure (P6 3 /mmc; space group no. 194), stands out: Similarly to WZ it is based on a hexagonal lattice, but the basis atoms along the c direction are arranged to form stoichiometric planes (see Fig.…”

Section: Introductionmentioning

confidence: 99%

Nonequilibrium BN-ZnO: Optical properties and excitonic effects from first principles

Zhang

Schleife

2018

Phys. Rev. B

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The non-equilibrium boron nitride (BN) phase of zinc oxide (ZnO) has been reported for thin films and nanostructures, however, its properties are not well understood due to a persistent controversy that prevents reconciling experimental and first-principles results for its atomic coordinates. We use first-principles theoretical spectroscopy to accurately compute electronic and optical properties, including single-quasiparticle and excitonic effects: Band structures and densities of states are computed using density functional theory, hybrid functionals, and the GW approximation. Accurate optical absorption spectra and exciton binding energies are computed by solving the Bethe-Salpeter equation for the optical polarization function. Using this data we show that the band-gap difference between BN-ZnO and wurtzite (WZ) ZnO agrees very well with experiment when the theoretical lattice geometry is used, but significantly disagrees for the experimental atomic coordinates. We also show that the optical anisotropy of BN-ZnO differs significantly from that of WZ-ZnO, allowing to optically distinguish both polymorphs. By using the transfer-matrix method to solve Maxwell's equations for thin films composed of both polymorphs, we illustrate that this opens up a promising route for tuning optical properties.

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Section: Introductionmentioning

confidence: 99%

Nonequilibrium BN-ZnO: Optical properties and excitonic effects from first principles

Zhang

Schleife

2018

Phys. Rev. B

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“…Since ZnO is deposited on cubic NiO, the possibility of the formation of cubic ZnO with less stress is favourable in the present case. The appearance of only peak of ZnO at 2θ ~77.401° could be due to influence of synthesis condition and is consistent with similar type of observations …”

Section: Resultsmentioning

confidence: 93%

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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“…The relatively strong peak at 2θ = 34.22° is due to ZnO (002) plane. Other weaker ZnO peaks at 2θ = 31.21°, 38.17°, and 47.32° correspond to the (100), (101), and (102) planes, respectively .…”

Section: Methodsmentioning

confidence: 99%

“…A closer look at the XRD patterns shows that the ZnO involves a cubic zinc blende structure rather than the more stable wurtzite (hexagonal) structure. The peak at 2θ = 47.32° is characteristic for a cubic crystal . The occurrence of the cubic structure for ZnO is due to its deposition onto a silicon substrate which has a cubic structure as well .…”

Section: Methodsmentioning

confidence: 99%

Effect of ZnO‐based TCO on the performance of a‐Si H(n)/a‐Si H(i)/c‐Si H(p)/Al BSF(p+)/Al heterojunction solar cells

Selmane

Cheknane

Aillerie

et al. 2018

Env Prog and Sustain Energy

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Inclusion of ZnO‐based transparent conducting oxide (TCO) film layer into amorphous silicon/crystalline silicon (a‐Si/c‐Si) solar cell enhances its photovoltaic conversion efficiency. These findings have been confirmed here, using Afors HIT software. The simulation study is performed onto a solar cell that was originally lab prepared so as to use its measured parameters in the simulation. The ZnO‐based TCO films were electrodeposited on n‐type (100) silicon wafer and were simulated. X‐ray diffraction (XRD) pattern confirms the zinc blende nature of the TCO layer, and show that the preferred orientation of ZnO films is (002). Scanning electron microscopic (SEM) imaging confirms nano‐size nature of the ZnO based TCO film. For comparison purposes, cells with and without TCO layers are investigated by simulating photo‐current versus applied potential (J–V) plots. Values of fill factor (FF), short circuit current density (Jsc) open circuit potential (VCO) and conversion efficiency (η) are extracted. The energy band diagram, current density and charge carrier generation/recombination phenomena are in‐depth analyzed to understand the mechanism of enhancement in the hetero‐junction cell performance. Values of quantum efficiency (QE) are also simulated. The results show that the solar cell heterojunction is hypersensitive to the ZnO layer. The added value of using the ZnO‐based transparent conductive oxide (TCO) layer, in enhancing intrinsic thin layer (HIT) solar cell conversion efficiency, is assessed by critically comparing it with a control cell having no ZnO layer. © 2018 American Institute of Chemical Engineers Environ Prog, 2018 © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13114, 2019

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Stable zinc-blende ZnO thin films: formation and physical properties

Cited by 14 publications

References 24 publications

Nonequilibrium BN-ZnO: Optical properties and excitonic effects from first principles

Nonequilibrium BN-ZnO: Optical properties and excitonic effects from first principles

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

Effect of ZnO‐based TCO on the performance of a‐Si H(n)/a‐Si H(i)/c‐Si H(p)/Al BSF(p+)/Al heterojunction solar cells

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Stable zinc-blende ZnO thin films: formation and physical properties

Cited by 14 publications

References 24 publications

Nonequilibrium BN-ZnO: Optical properties and excitonic effects from first principles

Nonequilibrium BN-ZnO: Optical properties and excitonic effects from first principles

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

Effect of ZnO‐based TCO on the performance of a‐Si H(n)/a‐Si H(i)/c‐Si H(p)/Al BSF(p+)/Al heterojunction solar cells

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