Optical constants and band structure of trigonal NiO

Ghosh, Ayana; Nelson, C. M.; Abdallah, Lina; Zollner, Stefan

doi:10.1116/1.4932514

Cited by 19 publications

(8 citation statements)

References 45 publications

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“…This is consistent with the red-shift of the absorption edge shown in Figure 7. Generally, the fundamental band gap of NiO of about 3.9 eV is believed to correspond to the charge transition from valence band maximum to the unoccupied Ni 3d orbital [42][43][44][45]. This value is comparable to our results.…”

Section: Represents Ni 2+ Vacancies and Ni Nisupporting

confidence: 91%

The Influence of Oxygen Flow Ratio on the Optoelectronic Properties of p-Type Ni1−xO Films Deposited by Ion Beam Assisted Sputtering

et al. 2018

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In this work, p-type non-stoichiometric Ni 1−x O thin films were deposited by oxygen ion beam assisted RF sputtering on glass substrates. The influence of the oxygen flow ratio (0-100%) on the films' optoelectronic properties was investigated. In our experimental conditions, all the films are crystallized in the cubic NiO phase. However, their crystallinity and mean grain size decreases with increasing oxygen flow ratios. Meanwhile, the films' conductivity improves from 9.1 to 25.4 S•cm −1. This is due to the fact that the nickel vacancies along with hole carriers can be introduced into NiO films when they are deposited under higher oxygen flow ratio conditions. Thus, the O-rich environment is beneficial in enhancing the films' carrier concentrations. In addition, with an increasing oxygen flow ratio, the film's transmittance degrades. The direct optical band gap of Ni 1−x O films declines slightly from 3.99 to 3.95 eV, with the oxygen flow ratio increasing from 0% to 100%.

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Section: Represents Ni 2+ Vacancies and Ni Nisupporting

confidence: 91%

The Influence of Oxygen Flow Ratio on the Optoelectronic Properties of p-Type Ni1−xO Films Deposited by Ion Beam Assisted Sputtering

et al. 2018

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“…[14], however the general line shape and energy positions of distinguished features is in very good agreement to those of Refs. [46][47][48][49].…”

Section: F Optical Propertiesmentioning

confidence: 99%

Structural, optical, and electrical properties of unintentionally doped NiO layers grown on MgO by plasma-assisted molecular beam epitaxy

Budde

Tschammer

Franz

et al. 2018

Journal of Applied Physics

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NiO layers were grown on MgO(100), MgO(110) and MgO(111) substrates by plasma-assisted molecular beam epitaxy under Ni-flux limited growth conditions. Single crystalline growth with a cube-on-cube epitaxial relationship was confirmed by X-ray diffraction measurements for all used growth conditions and substrates except MgO(111). A detailed growth series on MgO(100) was prepared using substrate temperatures ranging from 20°C to 900°C to investigate the influence on the layer characteristics. Energy-dispersive X-ray spectroscopy indicated close-to-stoichiometric layers with an oxygen content of ≈ 47 at.% and ≈ 50 at.% grown under low and high O-flux, respectively. All NiO layers had a root-mean-square surface roughness below 1 nm, measured by atomic force microscopy, except for rougher layers grown at 900°C or using molecular oxygen. Growth at 900°C led to a significant diffusion of Mg from the substrate into the film. The relative intensity of the quasi-forbidden one-phonon Raman peak is introduced as a gauge of the crystal quality, indicating the highest layer quality for growth at low oxygen fluxes and high growth temperature, likely due to the resulting high adatom diffusion length during growth. Optical and electrical properties were investigated by spectroscopic ellipsometry and resistance measurements, respectively. All NiO layers were transparent with an optical band gap around 3.6 eV and semi-insulating at room temperature. However, changes upon exposure to reducing or oxidizing gases of the resistance of a representative layer at elevated temperature was able to confirm p-type conductivity, highlighting their suitability as a model system for research on oxide-based gas sensing.

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“…11, the absorption is orders of magnitude too high for a typical indirect band gap in a thin film. 30 Therefore, only the direct band gap should be extracted. Tauc plots for differently doped BaSnO 3 films and for SrSnO 3 are shown in Fig.…”

Section: Lettersmentioning

confidence: 99%

Structure and optical band gaps of (Ba,Sr)SnO3 films grown by molecular beam epitaxy

Schumann

Raghavan

Ahadi

et al. 2016

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Epitaxial growth of (BaxSr1−x)SnO3 films with 0 ≤ x ≤ 1 using molecular beam epitaxy is reported. It is shown that SrSnO3 films can be grown coherently strained on closely lattice and symmetry matched PrScO3 substrates. The evolution of the optical band gap as a function of composition is determined by spectroscopic ellipsometry. The direct band gap monotonously decreases with x from to 4.46 eV (x = 0) to 3.36 eV (x = 1). A large Burnstein-Moss shift is observed with La-doping of BaSnO3 films. The shift corresponds approximately to the increase in Fermi level and is consistent with the low conduction band mass.

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Optical constants and band structure of trigonal NiO

Cited by 19 publications

References 45 publications

The Influence of Oxygen Flow Ratio on the Optoelectronic Properties of p-Type Ni1−xO Films Deposited by Ion Beam Assisted Sputtering

The Influence of Oxygen Flow Ratio on the Optoelectronic Properties of p-Type Ni1−xO Films Deposited by Ion Beam Assisted Sputtering

Structural, optical, and electrical properties of unintentionally doped NiO layers grown on MgO by plasma-assisted molecular beam epitaxy

Structure and optical band gaps of (Ba,Sr)SnO3 films grown by molecular beam epitaxy

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