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標題: Ab-initio Study on Cr2+0.25Zn0.75Te, V2+0.25Zn0.75Te, and Mn2+0.25Zn0.75Te Femtosecond Laser and its Electro-Optical Characteristics
利用第一原理計算探討Cr2+0.25Zn0.75Te、V2+0.25Zn0.75Te及Mn2+0.25Zn0.75Te 飛秒雷射與電光特性
作者: Bang-Wun Lin
關鍵字: first-principles
band structure
density of state
引用: [1] [2] [3] J. Y. Sohn, Y. H. Ahn, D. J. Park, E. Oh, and D. S. Kim, “Tunable terahertz generation using femtosecond pulse shaping,” Applied Physics Letters, Vol. 81, pp 13-15, 2002. DOI: 10.1063/1.1490140. [4] H. Luo, and J. K. Furdyna, “The II-VI semiconductor blue-green laser: challenges and solution,” Semiconductor Science Technology, Vol. 10, pp 1041-1048, 1995. DOI: 10.1088/0268-1242/10/8/001. [5] B. J. Lee, V. C. Sundar, J. R. Heine, M. G. Bawendi, and K. F. Jensen, “Full Color Emission from II-VI Semiconductor Quantum Dot-Polymer Composites,” Advanced Materials, Vol. 12, pp 1103-1105, 2000. DOI: 10.1002/1521-4095. [6] D. V. Talapin, A. L. Rogach, E. V. Shevchenko, A. Kornowski, M. Haase, and H. Weller, “Dynamic Distribution of Growth Rates within the Ensembles of Colloidal II-VI and III-V Semiconductor Nanocrystals as a Factor Governing Their Photoluminescence Efficiency,” Journal of the American Chemical Society, Vol. 124, pp 5782-5790, 2002. DOI: 10.1021/ja0123599 . [7] T. D. Luccio, A. M. Laera, L. Tapfer, S. Kempter, R. Kraus, and B. Nickel, “Controlled Nucleation and Growth of CdS Nanoparticles in a Polymer Matrix,” Joumal of Physical Chemistry B, Vol. 110, pp 12603-12609, 2006. DOI: 10.1021/jp061003m. [8] R. L. Hengehold, and F. L. Pedrotti, “Electron Energy-Loss Spectra of ZnS, ZnSe, and ZnTe,” Physical Review B, Vol. 6, pp 3026-3031, 1972. DOI: 10.1103 /PhysRevB.6.3026. [9] M. A. Haase, J. Qui, J. M. Depuydt, and H. Cheng, “Blue‐green laser diodes,” Applied Physical Letter, Vol. 59, pp 1272-1283, 1991. DOI: 10.1063/1.105472. [10] A. Ishibashi, “II-VI blue-green light emitters,” Journal of Crystal Growth, Vol. 159, pp 555-565, 1996. DOI: 10.1016/0022-0248(95)00586-2. [11] U. Ozgur, Y. I. Alivov, C. Liu , A. Teke, M. A. Reshchikov, S. Doan, V. Avrutin, S. J. Cho, and H. Morkoc, “A comprehensive review of ZnO materials and devices,” Journal of Applied Physics, Vol. 98, pp 041301-1-041301-103, 2005. DOI: 10.1063 /1.1992666. [12] J. A. Ruffner, M. D. Himel, V. Mizrahi, G. Stegeman, and U. J. Gibson, “Effects of low substrate temperature and ion assisted deposition on composition, optical properties, and stress of ZnS thin films,” Applied Optics, Vol. 28, pp 5209-5214, 1989. DOI: 10.1364/AO.28.005209. [13] A. K. S. Aqili, A. Maqsood, and Z. Ali, “Properties of Ag doped ZnTe thin films by an ion exchange process,” Applied Surface Science, Vol. 191, pp 280-285, 2002. DOI: 10.1016/S0169-4332(02)00218-0. [14] I. L. Kuskovsky, Y. Gong, G. F. Neumark, M. C. Tamargo, “Photoluminescence and magneto-optical properties of multilayered type-II ZnTe/ZnSe quantum dots,” Superlattices and Microstructures, Vol. 47, pp 87-92, 2010. DOI: 10.1016/j.spm i.2009.07.035. [15] W. Wang, G. Xia, J. Zheng, L. Feng, and R. Hao, “Study of polycrystalline ZnTe (ZnTe:Cu) thin films for photovoltaic cells,” Journal Material Sciences:Mater Electron, Vol. 18, pp 427-431, 2007. DOI: 10.1007/s10854-006-9044-0. [16] M. Schall, and P. U. Jepsen, “Above-band gap two-photon absorption and its influence on ultrafast carrier dynamics in ZnTe and CdTe,” Applied Physics Letters. Vol. 80, pp 4771-4773, 2002. DOI: 10.1063/1.1489480. [17] D. H. Feng, X. Q. Pan, X. Li, T. Q. Jia, and Z. R. Sun, “Coherent acoustic phonon generation and detection by femtosecond laser pulses in ZnTe single crystals,” Journal of Applied Physics, Vol. 114, pp 093513-1-093513-5, 2013. DOI: 10.1063 /1.4820518. [18] A. Pistone, A. S. Arico, P. L. Antonucci, D. Silvestro, and V. Antonucci, “Preparation and characterization of thin film ZnCuTe semiconductors,” Solar Energy Materials and Solar Cells, Vol 53, pp 254-267, 1998. DOI: 10.1016 /S0927-0248(98)00013-0. [19] H. Saito, V. Zayets, S. Yamagata, and K. Ando, “Room-Temperature Ferromagnetism in a II-VI Diluted Magnetic Semiconductor Zn1-xCrxTe,” Physical Review Letters, Vol. 90, pp 207202-1-207202-4, 2003. DOI: 10.1103 /PhysRevLett.90.207202. [20] R. Amutha, A. Subbarayan, and R. Sathyamoorthy, “Influence of substrate temperature on microcrystalline tructure and optical properties of ZnTe thin films,” Crystal Research and Technology, Vol 41, pp 1174-1179, 2006. DOI: 10.1002 /crat.200610744. [21] W. Zhou, D. Tang, A. Pan, Q. Zhang, Q. Wan, and B. Zou, “Structure and Photoluminescence of Pure and Indium-Doped ZnTe Microstructures, ” Journal of Physical Chemistry C, Vol. 115, pp 1415-1421, 2010. DOI: 10.1021/jp1069237. [22] L. D. Deloach, R. H. Page, G. D. Wilke, S. A. payne, and W. F. Krupke, “Transition Metal-Doped Zinc Chalcogenides: Spectroscopy and Laser Demonstration of a New Class of Gain Media,” IEEE Journal of Quantum Electronics, Vol. 32, pp 885-895, 1996. DOI: 10.1109/3.502365. [23] A. G. Bluiett, U. Hommerich, R. T. Shah, S. B. Trivedi, S. W. Kutcher, and C. C. Wang, “Observation of Lasing from Cr2+:CdTe and Compositional Effects in Cr2+-Doped II-VI Semiconductors,” Journal of Electronic Materials, Vol. 31, pp 806-810, 2002. DOI: 10.1007/s11664-002-0241-1. [24] A. M. Sinyukov, and L. M. Hayden, “Generation and detection of terahertz radiation with multilayered electro-optic polymer films,” Optics Letters, Vol. 27, pp 55-57, 2002. DOI: 10.1364/OL.27.000055. [25] T. Loffler, T. Hahn, M. Thomson, F. Jacob, and H. G. Roskos, “Large-area electro-optic ZnTe terahertz emitters,” Optics Express, Vol. 13, pp 5353-5362, 2005. DOI: 10.1364/OPEX.13.005353. [26] J. Fan, L. Ouyang, X. Liu, D. Ding, J. K. Furdyna, D. J. Smith, and Y. H. Zhang, “Growth and material properties of ZnTe on GaAs, InP, InAs and GaSb(001) substrates for electronic and optoelectronic device applications,” Journal of Crystal Growth, Vol. 323, pp 127-131, 2011. DOI: 10.1016/j.jcrysgro.2010.11.164. [27] C. Inui, H. Kura, T. Sato, Y. Tsuge, S. Shiratori, H. Ohkita, A. Tagaya, and Y. Kpike, “Preparation of nanocomposite for optical application using ZnTe nanoparticles and a zero-birefringence polymer,” Journal of Materials Science, Vol. 42, pp 8144-8149, 2007. DOI: 10.1007/s10853-007-1712-9. [28] Q. Wu, and X. C. Zhang, “Design and Characterization of Traveling-Wave Electrooptic Terahertz Sensors,” IEEE Journal of Selected Topics in Quantum Electronics, Vol. 2, pp 693-700, 1996. DOI: 10.1109/2944.571769. [29] D. V. Linde, K. S. Tinten, and J. Bialkowski,“Laser–solid interaction in the femtosecond time regime,” Applied Surface Science, Vol. 109, pp 1-10, 1997. DOI: 10.1016/S0169-4332(96)00611-3. [30] I. Fischer, Y. Liu, and P. Davis, “Synchronization of chaotic semiconductor laser dynamics on subnanosecond time scales and its potential for chaos communication,” Physical Review A, Vol. 62, pp011801-1-011801-4, 2000. DOI: 10.1103/Phys RevA.62.011801. [31] B. J. Feldman, and M. S. Feld, “Theory of a High-Intensity Gas Laser,” Physical Review A, Vol. 1, pp 1375-1396, 1970. DOI: 10.1103/PhysRevA.1.1375. [32] W. M. Gibbons, P. J. Shannon, S. T. Sun, and B. J. Swetlin, “Surface-mediated alignment of nematic liquid crystals with polarized laser light,” Nature, Vol. 351, pp 49-50, 1991. DOI: 10.1038/351049a0. [33] D. V. Linde, and H. Schuler,“Breakdown threshold and plasma formation in femtosecond laser–solid interaction,” Journal of Optical Society of America , Vol. 13, pp 216-222, 1996. DOI: 10.1364/JOSAB.13.000216. [34] B. A. Ghani, and M. Hammadi,“Mathematical modeling of rubylaser as a pumping source of a self Q-switched distributed feedback dye laser,” Optics and Lasers in Engineering, Vol. 42, pp 603-612, 2004. DOI: 10.1016/ j.optlasen g.2004.04.002. [35] T. H. Maiman,“Stimulated Optical Radiation in Ruby,” Nature, Vol. 187, pp 493-494, 1960. DOI: 10.1038/187493a0. [36] S. P. Radovanovic, S. Ristic, J. Stasic, and M. Trtica, “A study of Roman glass from Mala Barutana/Belgrade Fortress irradiated with pulsed CO2, Nd:YAG and ruby laser — Comparison,” Journal of Non-Crystalline Solids, Vol. 358, pp 3048-3056, 2012. DOI: 10.1016/j.jnoncrysol.2012.07.034. [37] H. Liu, Y. Jia, J. R. V. Aldana, D. Jaque, and F. Chen, “Femtosecond laser inscribed cladding waveguides in Nd:YAG ceramics: Fabrication, fluorescence imaging and laser performance,” Optics Express, Vol. 20, pp 18620-18629, 2012. DOI: 10.1364/OE.20.018620. [38] C. P. J. Barty, C. L. Gordon, and B. E. Lemoff, “Multiterawatt 30-fs Ti:sapphire laser system,” Optics Letters, Vol. 19, pp 1442-1444, 1994. DOI: 10.1364/ OL. 19.001442. [39] Q. Fu, G. Mak, and H. M. V. Driel, “High-power, 62-fs infrared optical parametric oscillator synchronously pumped by a 76-MHz Ti:sapphire laser,” Optics Letters, Vol. 17, pp 1006-1008, 1992. DOI: 10.1364/OL.17.001006. [40] J. Zhou, G. Traft, C. P. Huang, M. M. Murnane, H. C. Kapteyn, and I. P. Christov, “Pulse evolution in a broad-bandwidth Ti:sapphire laser,” Optics Letters, Vol. 19, pp 1149- 1151, 1994. DOI: 10.1364/OL.19.001149. [41] M. Yin, H. P. Li, S. H. Tang, and W. Ji, “Determination of nonlinear absorption and refraction by single Z-scan method,” Applied Physcis B, Vol. 70, pp 587-591, 2000. DOI: 10.1007/s003409900156. [42] W. Q. He, C. M. Gu, and W. Z. Shen, “Direct evidence of Kerr-like nonlinearity by femtosecond Z-scan technique,”Optics Letters, Vol. 14, pp 5476-5483, 2006. DOI: 10.1364/OE.14.005476. [43] D. N. Erschens, D. T.urchinovich, and P. U. Jepsen, “Optimized Optical Rectification and Electro-optic Sampling in ZnTe Crystals with Chirped Femtosecond Laser Pulses,” Journal Infrared Milli Terahz Waves, Vol. 32, pp 1371-1381, 2011. DOI: 10.1007/s10762-011-9829-y. [44] A. Schneider, M. Stillhart, and P. Gunter, “High efficiency generation and detection of terahertz pulses using laser pulses at telecommunication wavelengths,” Optics Express, Vol. 14, pp 5376-5384, 2006. DOI: 10.1364/OE.14.005376. [45] G. Berden, S. P. Jamison, A. M. Macleod, W. A. Gillespie, B. Redlich, and A. F. G. Meer, “Electro-Optic Technique with Improved Time Resolution for Real-Time, Nondestructive,Single-Shot Measurements of Femtosecond Electron Bunch Profiles,” Physical Review Letters, Vol. 93, pp 114802-1-114802-4, 2004. DOI: 10.1103/PhysRevLett.93.114802. [46] M. E. Lee, Y. C. Yeh, Y. H. Chung, C. L. Wu, C. S. Yang, W. C. Chou, C. T. Guo, and D. J. Jang, “Carrier capture and relaxation of self-assembled ZnTe/ZnSe quantum dots prepared under Volmer–Weber and Stranski–Krastanow growth modes,” Physica E, Vol. 26, pp 422-426, 2005. DOI:10.1016/j.physe. 2004.08.092. [47] J. Bang, J. Park, J. H. Lee, N. Won, J. Nam, J. Lim, B. Y. Chang, H. J. Lee, B. Chon, J. Shin, J. B. Park, J. H. Choi, K. Cho, S. M. Park, T. Joo, and S. Kim, ” ZnTe/ZnSe (Core/Shell) Type-II Quantum Dots: Their Optical and Photovoltaic Properties,” Chemistry of Materials, Vol. 22, pp 233-240, 2010. DOI: 10.10 21/cm9027995. [48] S. Rawalekar, S. Kaniyankandy, S. Verma, and H. N. Ghosh, ” Effect of Surface States on Charge-Transfer Dynamics in Type II CdTe/ZnTe CoreShell Quantum Dots: A Femtosecond Transient Absorption Study,” Journal of Physical Chemistry C, Vol. 115, pp 12335-12342, 2011. DOI: 10.1021/jp202916v. [49] V. Y. Gaivoronskii, M. M. Nazarov, D. A. Sapozhnikov, E. V. Shepelyavyi, S. A. Shkelnyuk, A. P. Shkurinov, and A. V. Shuvaev, “Competition between linear and nonlinear processes during generation of pulsed terahertz radiation in a ZnTe crystal,” Quantum Electronics, Vol. 35, pp 407-414, 2005. DOI: 10.1070/QE20 05v035n05ABEH002805. [50] P. C. M. Planken, H. K. Nienhuys, H. J. Bakker, and T. Wenckebach, “Measurement and calculation of the orientation dependence of terahertz pulse detection in ZnTe,” Optical Society of America, Vol. 18, pp 313-317, 2001. DOI: 10.1364/JOSAB.18.000313. [51] A. A. Ibrahim, N. Z. Elsayed, M. A. Kaid, and A. Ashour, “Structural and electrical properties of evaporated ZnTe thin films,” Vaccum, Vol. 75, pp 189-194, 2004. DOI: 10.1016/j.vacuum.2004.02.005. [52] G. I. Rusu, P. Prepelita, N. Apetroaei, and G. Popa, “On the Electronic transport and Optical properties of ZnTe thin fims,” Journal of Optoelectronics and Advanced Materials, Vol 7, pp 829-835, 2005. [53] G. K. Rao, K. V. Bangera, and G. K. Shivakumar, “The effect of substrate temperature on the structural, optical and electrical properties of vacuum deposited ZnTe thin films,” Vacuum, Vol. 83, pp 1485-1488, 2009. DOI: 10.1016/ j.vacu um.2009.06.047. [54] S. D. Kshirsagar, M. G. Krishna, and S. P. Tewari, “Optical characteristics of wurtzite ZnTe thin films,” Materials Sciece in Semiconductor Processing, Vol. 16, pp 1002-1007, 2013. DOI: 10.1016/j.mssp.2013.02.015. [55] J. Zhao, Y. Zeng, C. Liua, L. Cui, and Y. Li, “Optimization of VI/II pressure ratio in ZnTe growth on GaAs(0 0 1) by molecular beam epitaxy,” Applied Surface Science, Vol. 256, pp 6881-6886, 2010. DOI: 10.1016/j.apsusc.2010.04.105. [56] M. Luo, B. L. Vanmil, R. P. Tompkins, T. H. Myers, and N. C. Giles, “Photoluminescence of ZnTe and ZnTe:Cr grown by molecular-beam epitaxy,” Journal of Applied Physics, Vol. 97, pp 013518-1-013518-7, 2005. DOI: 10.10 63/1.1827921. [57] D. C. Sharma, S. Srivastava, Y. K. Vijay, and Y. K. Sharma, “Preparation and characterization of the chromium doped ZnTe thin films,” Advanced Materials Letters, Vol. 4, pp 68-70, 2013. DOI: 10.5185/amlett.2013.icnano.118. [58] P. Hohenberg , and W. Kohn, ”Inhomogeneous electron gas,” Physical Review, Vol. 136, pp 864-871, 1964. DOI: 10.1103/PhysRev.136.B864. [59] W. Kohn , and L. J. Sham, ”Self-consistent equations including exchange and correlation effects,” Physical Review, Vol. 140, pp 1133-1138, 1965. DOI:10.11 03/PhysRev.140.A1133. [60] J. P. Perdew , and Y. Wang, “Accurate and simple density functional for the electronic exchange energy: generalized gradient approximation,” Physical Review B, Vol. 33, pp 8800-8802, 1986. DOI: 10.1103/PhysRevB.33.8800. [61] M. Ernzerhof, and G. E. Scuseria, “Assessment of the Perdew–Burke–Ernzerhof exchange-correlation functional,” Journal of Chemical Physics, Vol. 110, pp 5029-5036, 1999. DOI: 10.1063/1.478401. [62] M. C. Payne, M. P. Teter, D. C. Allan, T. A. Arias and J. D. Joannopoulos, “Iterative minimization techniques for ab initio total-energy calculations: molecular dynamics and conjugate gradients,” Reviews of Modern Physics, Vol. 64, pp 1045-1097, 1992. DOI: 10.1103/RevModPhys.64.1045 [63] T. Tanaka, Y. Kume, M. Nishio, Q. Guo, H. Ogawa, and A. Yoshida, “Fabrication of ZnTe Light-Emitting Diodes Using Bridgman-Grown Substrates,” Japan Journal of Applied Physics , Vol. 42, pp 362-364, 2003. DOI: 10.1143/JJAP.42.L362. [64] A. K. S. Aqili, Z. Ali, and A. Maqsood, “Optical and structural properties of two-sourced evaporated ZnTe thin films,” Applied Surface Science , Vol. 167, pp 1-11, 2000. DOI: 10.1016/S0169-4332(00)00498-0. [65] A. M. Salem, T. M. Dahy, and Y. A. El-Gendy, “Thickness dependence of optical parameters for ZnTe thin films deposited by electron beam gun evaporation technique” Physica B, Vol. 403, pp 3027-3033, 2008. DOI: 10.1016/j.phys b.2008.03.005. [66] Y. Chen, C. Marceau, W. Liu, Z. D. Sun, Y. Zhang, F. Theberge, M. Chateauneuf, J. Dubois, and S. L. Chin, “Elliptically polarized terahertz emission in the forward direction of a femtosecond laser filament in air,” Applied Physics Letters, Vol. 93, pp 231116-1-231116-3, 2008. DOI: 10.1063/1.3046781. [67] X. Chen, S. He, Z. Shen, F. L. Zhao, K. Y. Xu, G. Wang, R. Wang, and N. Dai, “Influence of nonlinear effects in ZnTe on generation and detection of terahertz waves,” Journal of Applied Physics, Vol. 105, pp 023106-1-023106-5, 2009. DOI: 10.1063/1.3068480. [68] M. Nazeri, and R. Massudi, “Study on the effect of dispersion of the probe pulse on measuring the THz pulse propagating in a ZnTe crystal,” Measurement Science And Technology, Vol. 21, pp 115601-1-11560-7, 2010. DOI: 10.1088 /0957-0 233/21/11/115601. [69] K. Sato, M. Hanafusa, A. Noda, A. Arakawa, M. Uchida, T. Asahi, and O. Oda,“ZnTe pure green light-emitting diodes fabricated by thermal diffusion,” Journal of Crystal Growth, Vol. 214, pp 1080-1084, 2000. DOI: 10.1016/S00 22-0248(00)00278-5. [70] T. Mahalingam, V. S. John, S. Rajendran, and P. J. Sebastian, “Electrochemical deposition of ZnTe thin films,” Semiconductor Science and Technology, Vol. 17, pp 465-470, 2002. DOI: 10.1088/0268-1242/17/5/310. [71] A. H. Reshak, and S. Auluck, “Ab initio calculations of the electronic, linear and nonlinear optical properties of zinc chalcogenides,” Physica B, Vol. 388, pp 34-42, 2007. DOI: 10.1016/j.physb.2006.05.003. [72] Y. Liu, and B. G. Liu, “First-principles study of half-metallic ferromagnetism and structural stability of CrxZn1−xTe,” Journal of Physics D: Applied Physics, Vol. 40, pp 6791-6796, 2007. DOI: 10.1088/0022-3727/40/21/04. [73] Y. Liua, and B. G. Liu, “Ferromagnetism in transition-metal-doped II–VI compounds,” Journal of Magnetism and Magnetic Materials, Vol. 307, pp 245-249, 2006. DOI: 10.1016/j.jmmm.2006.04.009. [74] J. Moreno, and J. M. Soler, “Optimal meshes for integrals in real- and reciprocal-space unit cells,” Physical Review B, Vol. 45, pp 891-898, 1992. DOI: 10.1103/PhysRevB.45.13891. [75] W. Qin, and P. Fraundorf, “Lattice parameters from direct-space images at two tilts,” Ultramicroscopy, Vol. 94, pp 245-262, 2003. [76] I. B. Bersuker, “Modern Aspects of the Jahn-Teller Effect Theory and Applications to Molecular Problems,” Chemistry Review, Vol. 101, pp 1067-1114, 2001. DOI: 10.1021/cr0004411 .
摘要: In this study, the band structure and partial density of state (PDOS) of ZnTe, Cr2+0.25Zn0.75Te, V2+0.25Zn0.75Te, and Mn2+0.25Zn0.75Te were analysed by performing first-principles calculations based on density functional theory. The ZnTe band gap of 1.23 eV and the valence band energy level E0 of -1.35 eV appeared Te-5p orbital dominated in the PDOS, and the conduction band energy level E1 of -0.13 eV appeared Zn-3d and Te-5p dominated. Regarding Cr2+0.25Zn0.75Te, V2+0.25Zn0.75Te, and Mn2+0.25Zn0.75Te, the energy levels of the band gaps were 0.49 eV, 0.25 eV, and 0.68 eV, respectively, and the defect levels |-2>, |-1>, |0>, and |1> appeared to be Cr-3d, V-3d, Mn-3d, and Te-5p orbital dominated in the PDOS. We observed narrowing of the transition metal doped in the ZnTe system band gap, then generated the defect level. The property of the band structure was half metal. Degeneracy analysis was performed on the ZnTe band structures. Cr1+0.25Zn0.75Te and Cr2+0.25Zn0.75Te exhibited the same energy levels and wave function degeneracy phenomena, Cr1+0.125Zn0.875Te and Cr2+0.125Zn0.875Te exhibited nondegenerate phenomena that appeared split, and Cr1+0.03Zn0.97Te and Cr2+0.03Zn0.97Te exhibited enhanced nondegenerate phenomena.
本論文係以第一原理(First-principles)計算基於密度泛函理論(Density functional theory, DFT)對ZnTe與Cr2+0.25Zn0.75Te、V2+0.25Zn0.75Te及Mn2+0.25Zn0.75Te進行能帶結構與部分態密度(Partial Density of State, PDOS)進行研究,並透過能階分析了解ZnTe之元素的軌道貢獻。ZnTe的能隙值為1.23 eV而價電帶能階E0在-1.35 eV由PDOS顯示Te-5p軌道主導,導電帶能階E1在-0.13 eV顯示為Zn-3d與Te-5p軌道所主導, Cr2+0.25Zn0.75Te、V2+0.25Zn0.75Te及Mn2+0.25Zn0.75Te能隙值為0.49 eV、0.25 eV及0.68 eV,而Cr2+0.25Zn0.75Te、V2+0.25Zn0.75Te及Mn2+0.25Zn0.75Te結構,三者的缺陷能階|-2>、|-1>及|0>與導電帶能階|1>都由Cr-3d、V-3d及Mn-3d軌道與Te-5p軌道所主導。可得知過渡金屬摻雜於ZnTe中使能隙變窄產生缺陷能階提供電子躍遷而能帶結構方面價電帶跨越費米能階會呈現半金屬特性。ZnTe簡併分析以能帶結構圖觀察,Cr1+0.25Zn0.75Te與Cr2+0.25Zn0.75Te波函數具有相同能量而發生簡併現象,Cr1+0.125Zn0.875Te與Cr2+0.125Zn0.875Te能級產生分裂出現非簡併現象,而Cr1+0.03Zn0.97Te與Cr2+0.03Zn0.97Te的非簡併現象更為劇烈。
文章公開時間: 2017-10-31
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