Intrinsic surface band bending inCu3N(100)ultrathin films

Abstract

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.

Nonmagneticγ″-FeNthin films epitaxially grown on Cu(001): Electronic structure and thermal stability

“…The change in the LEED pattern is observed above 650 K. No change in the Cu LVV spectra ͑not shown͒ was detected during the transformation, indicating that there is no diffusion into the Cu substrate of the N atoms released and formation of copper nitrides. 32 The transformation of ␥Љ-FeN into ␥Ј-Fe 4 N upon heating is clearly observed in the photoemission spectra. Figure 4͑c͒ shows the N 1s and Fe 2p core levels for a ␥Љ-FeN thin film grown at 300 K and annealed in situ to 715 K. The relative intensity of the N 1s core level decreases, indicating the desorption of N upon annealing.…”

“…The N at the surface can also be detected clearly as a lower BE peak at 397.7 eV for ␥Ј-Fe 4 N. This surface nitrogen XPS position has already been discussed elsewhere. 9,32 Taking into account that the N atoms in the ␥Љ-FeN structure are in tetrahedral sites with four Fe atoms in their nearest-neighbor shell and are out of the Fe atomic plane, it is understandable that the N 1s XPS peak appears closer to that of N adsorbed at the Fe͑001͒ surface ͑where there are also four Fe atoms in the nearest-neighbor shell and the N is slightly out of the Fe plane͒ than to the ␥Ј-Fe 4 N, where the N atoms have a coordination shell of six Fe atoms and are located within the Fe plane.…”

Thermal stability of copper nitride thin films: The role of nitrogen migration

“…Finally, Cu 3 N has been also suggested to be used as a barrier material in tunnel junctions, 16 as a substrate for the growth of single-crystals of porphyrins and of atomic nanowires 17 and as a good candidate for hybrid inorganic-organic solar cells. 2 From a fundamental point of view the family of Cu-N compounds offers a rich variety of electronic properties depending on chemical composition, ranging from fully metallic ͑Cu 4 N͒ ͑Ref. 18͒ to semiconducting ͑Cu 3 N͒ behavior.…”

Stopping power dependence of nitrogen sputtering yields in copper nitride films under swift-ion irradiation: Exciton model approach

“…1 by a dashed line. The fitting parameters are listed in Table 1, where the saturation level for the nitrogen depleted from the film, Nf, has been fixed at ~18 x 10 21 atoms/ cm 3 . The normalized root-mean square deviation (a) to assess the goodness of the fits is also included in the Table 1.…”

“…Copper nitride is a semiconducting material with an optical bandgap of around 1 eV [1][2][3] which presents a cubic lattice structure. Cu 3 N thin films are usually deposited by sputtering [4,5].…”