Energy band-gap calculation of δ-Ta₂O₅ using sX-LDA and B3LYP methods

Abstract

The energy band-gap and related factors of tantalum pentoxide with hexagonal phase were investigated using hybrid functional B3LYP and sX-LDA methods. The results showed that both sX-LDA and B3LYP techniques reveal the indirect semiconductor nature of δ-Ta₂O₅, whereas the obtained value of energy band-gap is much higher than previous theoretical reports but closer to the experimental data. The optical bandgap of δ-Ta₂O₅ is expected to originate from the O 2p→Ta 5d transition which may benefit from the d-s-p hybridization.

Keywords

Ta₂O₅ / B3LYP / hexagonal phase / sX-LDA / band-gap

References

[1] Chaneliere C, Autran J, Devine R, . Tantalum Pentoxide (Ta₂O₅) Thin Films for Advanced Dielectric Applications [J]. Mat. Sci. Eng., 1998, R22: 269-322.

[2] Andreoni W, Pignedoli C A Ta₂O₅ Polymorphs: Structural Motifs and Dielectric Constant from First Principles[J]. Appl. Phys. Lett., 2010, 96: 062901

[3] Fujikawa H, Taga Y Effects of Additive Elements on Electrical Properties of Tantalum Oxide Films[J]. J. Appl. Phys., 1994, 75: 2 538

[4] Stephenson N, Roth R Structural Systematics in the Binary System Ta₂O₅-WO₃. IV. The Structure of Ta₃₈WO₉₈ [J]. Acta Crystallogr., Sect B. Struct. Sci., 1971, 27: 1 031-1 036.

[5] Fukumoto A, Miwa K Prediction of Hexagonal Ta₂O₅ Structure by First-Principles Calculations[J]. Phys. Rev. B, 1997, 55: 11 155

[6] Gu T K, Wang Z C, Tada T, . First-Principles Simulations on Bulk Ta₂O₅ and Cu/Ta₂O₅ /Pt Heterojunction:Electronic Structures and Transport Properties[J]. J. Appl. Phys., 2009, 106: 103 713

[7] Sahu B R, Kleinman L Theoretical Study of Structural and Electronic Properties of b-Ta₂O₅ and d-Ta₂O₅[J]. Phys. Rev. B, 2004, 69: 165 202

[8] Perdew J P, Wang Y Accurate and Simple Analytic Representation of the Electron-Gas Correlation Energy[J]. Phys. Rev. B, 1992, 45: 13 244-13 249.

[9] Blaha P, Schwarz K, Madsen G, . Computer Code WIEN2K[M], 2001 Vienna: Vienna University of Technology Press

[10] Seid A, Gorling A, Vog P, . Generalized Kohn-Sham Schemes and the Band-Gap Problem[J]. Phys. Rev. B, 1996, 53: 3 764-3 774.

[11] Becke A D Density-Functional ThermoChemistry. III. The Role of Exact Exchange [J]. J. Chem. Phys., 1993, 98: 5 648-5 652.

[12] Wu X M, Soss S R, Rymaszewski E J, . Dielectric Constant Dependence of Poole-Frenkel Potential in Tantalum Oxide Thin Films [J]. Mater. Chem. Phys., 1994, 38: 297

[13] Fleming R M, Lang D V, Jones C D, . Defect Dominated Charge Transport in Amorphous Ta₂O₅ Thin Films[J]. J. Appl. Phys., 2000, 88: 850-862.

[14] Qin G Q, Zhang G L, Yu G, . Electronic Band Gap of ZnO under Triaxial Strain [J]. J.Wuhan.Univ.Technol-Mater. Sci. Ed., 2013, 28: 48-51.

[15] Duan Y H, Sun Y, Peng M J, . Calculated Structure, Elastic and Electronic Properties of Mg₂Pb at High Pressure [J]. J. Wuhan. Univ. Technol-Mater. Sci. Ed., 2012, 27: 377-381.

[16] Perdew J P, Burke K, Ernzerhof M Generalized Gradient Approximation Made Simple[J]. Phys. Rev. Lett., 1996, 77: 3 865-3 868.

[17] Vanderbilt D Soft Self-consistent Pseudopotentials in a Generalized Eigenvalue Formalism[J]. Phys. Rev. B, 1990, 41: 7 892-7 895.