Optical and transport properties of LaTi_{1鈭?span style='font-style: italic'>x}M_x(O,N)_3卤未 (x=0; 0.1, M=Nb⁵⁺, W⁶⁺) thin films prepared by plasma ammonolysis

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• 作者：Alex ; ra E. Maegli ; Leyre Sagarna ; Sascha Populoh ; Bartosz Penkala ; Eugenio H. Otal ; Anke Weidenkaff
• 关键词：Thin films ; Microwave-induced plasma ammonolysis ; X-ray photoelectron spectroscopy ; UV&ndash ; Vis transmittance ; Electronic properties
• 刊名：Journal of Solid State Chemistry
• 出版年：March, 2014
• 年：2014
• 卷：211
• 期：Complete
• 页码：106-112
• 全文大小：1879 K

文摘

Oxynitride thin films of composition LaTi_1鈭?em>xM_x(O,N)_3卤未 with x=0; 0.1 and M=Nb⁵⁺, W⁶⁺ were prepared by nitridation via microwave-induced plasma (MIP) ammonolysis, which allowed keeping the nitridation time short (16 min). The higher possible oxidation states of the B-site substituents (Nb⁵⁺, W⁶⁺) with respect to Ti⁴⁺ caused higher N content for LaTi_0.9Nb_0.1(O,N)_3卤未 and LaTi_0.9W_0.1(O,N)_3卤未 compared to LaTiO₂N due to charge-compensation. XPS O 1s and N 1s core level and valence band spectra evidenced for increasing N content in the order LaTiO₂N<LaTi_0.9Nb_0.1(O,N)_3卤未<LaTi_0.9W_0.1(O,N)_3卤未. All films were N deficient comparing with their stoichiometric formulas and assuming cations in highest oxidation states. Along with increasing N content, the bandgaps decreased from 2.4 to 2.2 and 2.1 eV for LaTiO₂N, LaTi_0.9Nb_0.1(O,N)_3卤未, and LaTi_0.9W_0.1(O,N)_3卤未 and the electronic conductivities increased along with the decreased bandgaps. The Seebeck coefficients at 860 K indicated the highest charge-carrier density for LaTi_0.9W_0.1(O,N)_3卤未.