Ab initio total energy calculations of copper nitride: the effect of lattice parameters and Cu content in the electronic properties

Moreno-Armenta, María G.; Martı́nez-Ruiz, Alejandro; Takeuchi, Noboru

doi:10.1016/j.solidstatesciences.2003.10.014

Cited by 90 publications

(48 citation statements)

References 16 publications

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“…Much of the previous DFT work on Cu 3 N uses functionals likely to inaccurately determine the band gap [64][65][66]. Evaluation of the HSE06 band structure along a reciprocal space path tracing all edges of the irreducible primitive cubic Brillouin zone [67] [see Fig.…”

Section: Theoretical Studiesmentioning

confidence: 99%

Atypically small temperature-dependence of the direct band gap in the metastable semiconductor copper nitrideCu3N

et al. 2017

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The temperature-dependence of the direct band gap and thermal expansion in the metastable anti-ReO 3 semiconductor Cu 3 N are investigated between 4.2 and 300 K by Fourier-transform infrared spectroscopy and x-ray diffraction. Complementary refractive index spectra are determined by spectroscopic ellipsometry at 300 K. A direct gap of 1.68 eV is associated with the absorption onset at 300 K, which strengthens continuously and reaches a magnitude of 3.5×10 5 cm −1 at 2.7 eV, suggesting potential for photovoltaic applications. Notably, the direct gap redshifts by just 24 meV between 4.2 and 300 K, giving an atypically small band-gap temperature coefficient dE g /dT of −0.082 meV/K. Additionally, the band structure, dielectric function, phonon dispersion, linear expansion, and heat capacity are calculated using density functional theory; remarkable similarities between the experimental and calculated refractive index spectra support the accuracy of these calculations, which indicate beneficially low hole effective masses and potential negative thermal expansion below 50 K. To assess the lattice expansion contribution to the band-gap temperature-dependence, a quasiharmonic model fit to the observed lattice contraction finds a monotonically decreasing linear expansion (descending past 10 −6 K −1 below 80 K), while estimating the Debye temperature, lattice heat capacity, and Grüneisen parameter. Accounting for lattice and electron-phonon contributions to the observed band-gap evolution suggests average phonon energies that are qualitatively consistent with predicted maxima in the phonon density of states. As band-edge temperature-dependence has significant consequences for device performance, copper nitride should be well suited for applications that require a largely temperature-invariant band gap.

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Section: Theoretical Studiesmentioning

confidence: 99%

Atypically small temperature-dependence of the direct band gap in the metastable semiconductor copper nitrideCu3N

et al. 2017

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“…Previous theoretical calculations predict a band gap of either 0.23 eV ͑using linear augmented plane wave 19 ͒ or 0.9 eV ͑using linear combination of atomic orbitals͒. 20 The gaps determined experimentally are generally larger but vary widely from 0.8 to 1.9 eV. 3,4,6 This could indicate that the actual composition and microstructure of the material and, thus, its band gap depend on the experimental conditions.…”

Section: Introductionmentioning

confidence: 97%

Intrinsic surface band bending inCu3N(100)ultrathin films

et al. 2007

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Highly homogeneous, ultrathin films of copper nitride ͑Cu 3 N͒ have been grown on Fe͑001͒ at room temperature using a Cu evaporator and a radio-frequency plasma source to obtain atomic nitrogen in a UHV environment. Cu 3 N is a semiconductor with the valence band edge at −0.65± 0.05 eV below the Fermi Level. The formation of copper nitride can be detected spectroscopically by the shape of the Cu LVV-Auger electron transition, which changes sensibly in shape and position compared to metallic Cu. Cu 3 N grows epitaxially with the substrate forming flat disklike mosaic blocks, ͑001͒ oriented. Both x-ray core level photoelectron spectroscopy and ultraviolet photoelectron spectroscopy photoemission experiments have been used to study the electronic structure. A first-principles calculation has been performed and compared with the measured spectra.

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“…Extra Cu atoms can lower the optical bandgap as well as increase the lattice parameter and the conductivity of Cu-rich nitride films. [5] Cu 3 N is stable at room temperature and decomposes to make pure copper metal films at temperatures of ca. 250-450°C.…”

Section: Introductionmentioning

confidence: 99%

Thin, Continuous, and Conformal Copper Films by Reduction of Atomic Layer Deposited Copper Nitride

Gordon

2006

Chemical Vapor Deposition

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Thin and continuous copper films serve as seed layers for electrodeposition of interconnects in microelectronic devices. Gaps in the continuity of these Cu films must be avoided, because they can generate voids that later lead to failure of the devices. It is difficult to sputter completely continuous copper-seed layers into the increasingly narrow trenches and holes in modern interconnects. Here we report a method for producing thin, completely continuous, and highly conductive copper films conformally inside very narrow holes with aspect ratios of over 40:1. The first step in our process is atomic layer deposition (ALD) of copper(I) nitride, Cu 3 N, by the alternating reactions of copper(I) N,N′-di-sec-butylacetamidinate vapor and ammonia on surfaces heated to approximately 160°C. At this temperature, Cu 3 N is thermally stable, but is readily reduced to copper metal by exposure to molecular hydrogen gas (H 2 ). Copper layers as thin as 0.8 nm (about 3 monolayers) are electrically continuous and show the electrical resistivity predicted by a grain-boundary-scattering model for continuous films of that thickness. 3 nm thick copper films on 2 nm of ruthenium have a sheet resistance of less than 50 X/ᮀ, a value low enough to serve as seed layers for advanced electroplating techniques.

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Ab initio total energy calculations of copper nitride: the effect of lattice parameters and Cu content in the electronic properties

Cited by 90 publications

References 16 publications

Atypically small temperature-dependence of the direct band gap in the metastable semiconductor copper nitrideCu3N

Atypically small temperature-dependence of the direct band gap in the metastable semiconductor copper nitrideCu3N

Intrinsic surface band bending inCu3N(100)ultrathin films

Thin, Continuous, and Conformal Copper Films by Reduction of Atomic Layer Deposited Copper Nitride

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