Title

Growth and physical properties of epitaxial CeN layers on MgO(001)

Document Type

Article

Publication Date

7-15-2003

Abstract

Growth and physical properties of epitaxial CeN layers on MgO were investigated. The films were grown by ultrahigh vacuum reactive magnetron sputter deposition. X-ray diffraction and transmission electron microscopy were used for the analysis. The hardness and elastic modulus of CeN were determined from nanoindentation measurements. While NaCl-structure transition-metal nitrides have been widely studied over the past two decades, little is known about the corresponding NaCl-structure rare-earth nitrides. Polycrystalline CeN, for example, has been reported by different groups to be both a wide band-gap semiconductor and a metal. To address this controversy, we have grown epitaxial CeN layers on MgO(001) and measured their physical properties. The films were grown at 700 °C">700 °C700 °C by ultrahigh vacuum reactive magnetron sputter deposition in mixed Ar/N2">Ar/N2Ar/N2 discharges maintained at 4 mTorr (0.53 Pa). X-ray diffraction and transmission electron microscopy results establish the film/substrate epitaxial relationship as cube-on-cube, (001)CeN‖(001)MgO">(001)CeN‖(001)MgO(001)CeN‖(001)MgO with [100]CeN‖[100]MgO,">[100]CeN‖[100]MgO,[100]CeN‖[100]MgO, while Rutherford backscattering spectroscopy shows that the layers are stoichiometric with N/Ce=0.99±0.02.">N/Ce=0.99±0.02.N/Ce=0.99±0.02. CeN is metallic with a positive temperature coefficient of resistivity and a temperature-independent carrier concentration, as determined by Hall effect measurements, of 2.8±0.2×1022 cm−3">2.8±0.2×1022 cm−32.8±0.2×1022 cm−3 with a room temperature mobility of 0.31 cm2 V−1 s−1.">0.31 cm2 V−1 s−1.0.31 cm2 V−1 s−1. At temperatures between 2 and 50 K, the resistivity is limited by defect scattering and remains constant at 29 μΩ cm,">29 μΩ cm,29 μΩ cm, while at higher temperatures it increases linearly, limited primarily by phonon scattering, to reach a room-temperature value of 68.5 μΩ cm.">68.5 μΩ cm.68.5 μΩ cm. The hardness and elastic modulus of CeN(001) were determined from nanoindentation measurements to be 15.0±0.9">15.0±0.915.0±0.9 and 330±16 GPa.">330±16 GPa.330±16 GPa.

REFERENCES

Comments

Originally published as:

Lee, T.-Y., Gall, D., Shin, C.-S., Hellgren, N., Petrov, I., & Greene, J. E. (2003). Growth and physical properties of epitaxial CeN layers on MgO(001). Journal of Applied Physics, 94(2), 921–927. https://doi.org/10.1063/1.1579113

Link to Full Text

  Contact Author

Share

COinS