[en] The impact of different synthesis parameters, such as thickness, postsynthesis annealing temperature, and oxygen gas flow rate, upon the electronic structure is discussed in detail in the present experimental investigation. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) spectroscopy techniques are used to evaluate the surface electronic properties along with the presence and stability of the CdO2 surface oxide in CdxZn1−xO (x = 0.4) composite thin films. The thin films were synthesized with varying thicknesses using a Cd0.4Zn0.6O (CZO) ceramic and Cd0.4Zn0.6 (CZ) metallic targets and oxygen gas flow rates during magnetron sputtering. The Zn L3,2 edge and O K edge XANES spectra are affected by the oxygen gas flow rate. For the zero rate, an increase in intensity is observed in the Zn L3,2 edge, and notable changes occur in the overall spectral features of the O K edge. In the films synthesized in the presence of oxygen, highly probable O 2p → antibonding Zn 3d electronic transitions decrease the probability of the Zn 2p1/2 → antibonding Zn 3d electronic transition by filling the vacant antibonding Zn
3d states, leading to the reduction in overall intensity in the Zn L3,2 edge. Scanning electron microscopy reveals grain growth with increasing annealing temperature. The annealing induces orbital hybridization, generating new electronic states with higher
transition probabilities and intensity enhancement in both Zn L3,2 and O K edges. The presence of the CdO2 surface phase is confirmed by analyzing the Cd 3d5/2 and O 1s XPS core levels. The CdO2 surface phase is observed in the films synthesized using the CZO target for all thicknesses, while the CZ target is only observed for higher thicknesses. Further postsynthesis annealing treatment results in the disappearance of the CdO2 phase. The CdO2 surface phase can be controlled by varying the film thickness and postsynthesis annealing temperature.
Disciplines :
Chemistry
Author, co-author :
Das, Arkaprava ; Université de Mons - UMONS > Faculté des Sciences > Service de Chimie des Interactions Plasma-Surface
Partyka-Jankowska, Ewa; SOLARIS National Synchrotron Radiation Centre, Jagiellonian University, Czerwone Maki 98, 31-007 Krakow, Poland
Zając, Marcin; SOLARIS National Synchrotron Radiation Centre, Jagiellonian University, Czerwone Maki 98, 31-007 Krakow, Poland
Hemberg, Axel; Materia Nova, Nicolas Copernic 3, 7000 Mons, Belgium
Bittencourt, Carla ; Université de Mons - UMONS > Faculté des Sciences > Service de Chimie des Interactions Plasma-Surface
Language :
English
Title :
Impact of Synthesis Parameters upon the Electronic Structure in PVD-Deposited CdxZn1xO Composite Thin Films: An XPS-XANES Investigation
Devi, V.; Kumar, M.; Shukla, D. K.; Choudhary, R. J.; Phase, D. M.; Kumar, R.; Joshi, B. C. Structural, optical and electronic structure studies of Al doped ZnO thin films. Superlattices Microstruct. 2015, 83, 431- 438, 10.1016/j.spmi.2015.03.047
Masui, H.; Nakamura, S.; DenBaars, S. P.; Mishra, U. K. Nonpolar and semipolar III-nitride light-emitting diodes: Achievements and challenges. IEEE Trans. Electron Devices 2010, 57, 88- 100, 10.1109/TED.2009.2033773
Ambacher, O. Growth and applications of group III-nitrides. J. Phys. D: Appl. Phys. 1998, 31, 2653, 10.1088/0022-3727/31/20/001
Özgür, Ü.; Alivov, Y. I.; Liu, C.; Teke, A.; Reshchikov, M. A.; Doğan, S.; Avrutin, V.; Cho, S.-J.; Morkoç, H. A comprehensive review of ZnO materials and devices. J. Appl. Phys. 2005, 98, 041301 10.1063/1.1992666
Janotti, A.; Van de Walle, C. G. Fundamentals of zinc oxide as a semiconductor. Rep. Prog. Phys. 2009, 72, 126501 10.1088/0034-4885/72/12/126501
Schleife, A.; Rödl, C.; Furthmüller, J.; Bechstedt, F. Electronic and optical properties of MgxZn1- xO and CdxZn1- xO from ab initio calculations. New J. Phys. 2011, 13, 085012 10.1088/1367-2630/13/8/085012
Yu, K. M.; Mayer, M. A.; Speaks, D. T.; He, H.; Zhao, R.; Hsu, L.; Mao, S. S.; Haller, E. E.; Walukiewicz, W. Ideal transparent conductors for full spectrum photovoltaics. J. Appl. Phys. 2012, 111, 123505 10.1063/1.4729563
Yang, Y.; Jin, S.; Medvedeva, J. E.; Ireland, J. R.; Metz, A. W.; Ni, J.; Hersam, M. C.; Freeman, A. J.; Marks, T. J. CdO as the archetypical transparent conducting oxide. Systematics of dopant ionic radius and electronic structure effects on charge transport and band structure. J. Am. Chem. Soc. 2005, 127, 8796- 8804, 10.1021/ja051272a
Yan, M.; Lane, M.; Kannewurf, C. R.; Chang, R. P. H. Highly conductive epitaxial CdO thin films prepared by pulsed laser deposition. Appl. Phys. Lett. 2001, 78, 2342- 2344, 10.1063/1.1365410
Tamayo-Arriola, J.; Huerta-Barberà, A.; Montes Bajo, M.; Muñoz, E.; Muñoz-Sanjosé, V.; Hierro, A. Rock-salt CdZnO as a transparent conductive oxide. Appl. Phys. Lett. 2018, 113, 222101 10.1063/1.5048771
Zhu, W.; Yu, K. M.; Walukiewicz, W. Indium doped Cd1-xZnxO alloys as wide window transparent conductors. Thin Solid Films 2015, 597, 183- 187, 10.1016/j.tsf.2015.11.052
Detert, D. M.; Lim, S. H. M.; Tom, K.; Luce, A. V.; Anders, A.; Dubon, O. D.; Yu, K. M.; Walukiewicz, W. Crystal structure and properties of CdxZn1- xO alloys across the full composition range. Appl. Phys. Lett. 2013, 102, 232103 10.1063/1.4809950
Ishihara, J.; Nakamura, A.; Shigemori, S.; Aoki, T.; Temmyo, J. Zn1- xCdxO systems with visible band gaps. Appl. Phys. Lett. 2006, 89, 091914 10.1063/1.2345232
Ohashi, T.; Yamamoto, K.; Nakamura, A.; Aoki, T.; Temmyo, J. Optical Properties of Wurtzite Zn1-xCdxO Films Grown by Remote-Plasma-Enhanced Metalorganic Chemical Vapor Deposition. Jpn. J. Appl. Phys. 2007, 46, 2516, 10.1143/JJAP.46.2516
Ma, X.; Chen, P.; Zhang, R.; Yang, D. Optical properties of sputtered hexagonal CdZnO films with band gap energies from 1.8 to 3.3 eV. J. Alloys Compd. 2011, 509, 6599- 6602, 10.1016/j.jallcom.2011.03.101
Detert, D. M.; Tom, K. B.; Battaglia, C.; Denlinger, J. D.; Lim, S. H. N.; Javey, A.; Anders, A.; Dubon, O. D.; Yu, K. M.; Walukiewicz, W. Fermi level stabilization and band edge energies in CdxZn1- xO alloys. J. Appl. Phys. 2014, 115, 233708 10.1063/1.4884683
Venkatachalapathy, V.; Galeckas, A.; Trunk, M.; Zhang, T.; Azarov, A.; Kuznetsov, A. Y. Understanding phase separation in ZnCdO by a combination of structural and optical analysis. Phys. Rev. B 2011, 83, 125315 10.1103/PhysRevB.83.125315
Schleife, A.; Eisenacher, M.; Rödl, C.; Fuchs, F.; Furthmüller, J.; Bechstedt, F. Ab initio description of heterostructural alloys: Thermodynamic and structural properties of Mg x Zn 1- x O and Cd x Zn 1- x O. Phys. Rev. B 2010, 81, 245210 10.1103/PhysRevB.81.245210
Singh, T.; Lehnen, T.; Leuning, T.; Sahu, D.; Mathur, S. Thickness dependence of optoelectronic properties in ALD grown ZnO thin films. Appl. Surf. Sci. 2014, 289, 27- 32, 10.1016/j.apsusc.2013.10.071
Xu, L.; Li, X.; Chen, Y.; Xu, F. Structural and optical properties of ZnO thin films prepared by sol-gel method with different thickness. Appl. Surf. Sci. 2011, 257, 4031- 4037, 10.1016/j.apsusc.2010.11.170
Beigi, L.; Saheb, V. A facile one-pot method for the synthesis of CdO2 and CdO nanoparticles by oxidation of cadmium metal by hydrogen peroxide. Nano-Struct. Nano-Objects 2017, 9, 13- 18, 10.1016/j.nanoso.2016.12.001
Zając, M.; Giela, T.; Freindl, K.; Kollbek, K.; Korecki, J.; Madej, E.; Pitala, K.; Kozioł-Rachwał, A.; Sikora, M.; Spiridis, N. The first experimental results from the 04BM (PEEM/XAS) beamline at Solaris. Nucl. Instrum Methods Phys. Res. B 2021, 492, 43- 48, 10.1016/j.nimb.2020.12.024
Szlachetko, J.; Szade, J.; Beyer, E.; Błachucki, W.; Ciochoń, P.; Dumas, P.; Freindl, K.; Gazdowicz, G.; Glatt, S.; Guła, K. SOLARIS national synchrotron radiation centre in Krakow, Poland. Eur. Phys. J. Plus 2023, 138 ( 1), 10, 10.1140/epjp/s13360-022-03592-9
Das, A.; Saini, C. P.; Singh, D.; Ahuja, R.; Kaur, A.; Aliukov, S.; Shukla, D.; Singh, F. High temperature-mediated rocksalt to wurtzite phase transformation in cadmium oxide nanosheets and its theoretical evidence. Nanoscale 2019, 11, 14802- 14819, 10.1039/C9NR01832H
Das, A.; Singh, D.; Saini, C. P.; Ahuja, R.; Kaur, A.; Aliukov, S. Orbital hybridization-induced band offset phenomena in Ni x Cd 1- x O thin films. Nanoscale 2020, 12, 669- 686, 10.1039/C9NR05184H
Piper, L. F. J.; Jefferson, P. H.; Veal, T. D.; McConville, C. F.; Zuñiga-Pérez, J.; Munoz-Sanjosé, V. X-ray photoemission studies of the electronic structure of single-crystalline CdO (100). Superlattices Microstruct. 2007, 42, 197- 200, 10.1016/j.spmi.2007.04.029
Meng, F.; Ge, F.; Chen, Y.; Xu, G.; Huang, F. Local structural changes induced by ion bombardment in magnetron sputtered ZnO: Al films: Raman, XPS, and XAS study. Surf. Coat. Technol. 2019, 365, 2- 9, 10.1016/j.surfcoat.2018.04.013
Faiz, M.; Tabet, N.; Mekki, A.; Mun, B. S.; Hussain, Z. X-ray absorption near edge structure investigation of vanadium-doped ZnO thin films. Thin Solid Films 2006, 515, 1377- 1379, 10.1016/j.tsf.2006.03.044
Chiou, J. W.; Kumar, K. P. K.; Jan, J. C.; Tsai, H. M.; Bao, C. W.; Pong, W.-F.; Chien, F. Z.; Tsai, M.-H.; Hong, I.-H.; Klauser, R. Diameter dependence of the electronic structure of ZnO nanorods determined by x-ray absorption spectroscopy and scanning photoelectron microscopy. Appl. Phys. Lett. 2004, 85, 3220- 3222, 10.1063/1.1802373
Chiou, J. W.; Jan, J. C.; Tsai, H. M.; Bao, C. W.; Pong, W.-F.; Tsai, M.-H.; Hong, I.-H.; Klauser, R.; Lee, J. F.; Wu, J. J.; Liu, S. C. Electronic structure of ZnO nanorods studied by angle-dependent x-ray absorption spectroscopy and scanning photoelectron microscopy. Appl. Phys. Lett. 2004, 84, 3462- 3464, 10.1063/1.1737075
Murphy, M. W.; Diebel, W. R.; Yiu, Y.-M.; Sham, T.-K. Cr doped ZnO nanostructures: synthesis, electronic structures, and magnetic properties. Can. J. Chem. 2017, 95, 1225- 1232, 10.1139/cjc-2017-0143
Mizoguchi, T.; Tanaka, I.; Yoshioka, S.; Kunisu, M.; Yamamoto, T.; Ching, W. Y. First-principles calculations of ELNES and XANES of selected wide-gap materials: dependence on crystal structure and orientation. Phys. Rev. B 2004, 70, 045103 10.1103/PhysRevB.70.045103
Gilbert, B.; Frazer, B. H.; Zhang, H.; Huang, F.; Banfield, J. F.; Haskel, D.; Lang, J. C.; Srajer, G.; De Stasio, G. X-ray absorption spectroscopy of the cubic and hexagonal polytypes of zinc sulfide. Phys. Rev. B 2002, 66, 245205 10.1103/PhysRevB.66.245205
Krishnamurthy, S.; McGuinness, C.; Dorneles, L. S.; Venkatesan, M.; Coey, J. M. D.; Lunney, J. G.; Patterson, C. H.; Smith, K. E.; Learmonth, T.; Glans, P.-A. Soft-x-ray spectroscopic investigation of ferromagnetic Co-doped ZnO. J. Appl. Phys. 2006, 99, 08M111 10.1063/1.2165916
Guo, J. H.; Vayssieres, L.; Persson, C.; Ahuja, R.; Johansson, B.; Nordgren, J. Polarization-dependent soft-x-ray absorption of highly oriented ZnO microrod arrays. J. Phys.: Condens. Matter 2002, 14, 6969, 10.1088/0953-8984/14/28/308
Frati, F.; Hunault, M. O. J. Y.; De Groot, F. M. F. Oxygen K-edge X-ray absorption spectra. Chem. Rev. 2020, 120, 4056- 4110, 10.1021/acs.chemrev.9b00439
McGuinness, C.; Stagarescu, C. B.; Ryan, P. J.; Downes, J. E.; Fu, D.; Smith, K. E.; Egdell, R. G. Influence of shallow core-level hybridization on the electronic structure of post-transition-metal oxides studied using soft X-ray emission and absorption. Phys. Rev. B 2003, 68, 165104 10.1103/PhysRevB.68.165104
Demchenko, I. N.; Chernyshova, M.; Tyliszczak, T.; Denlinger, J. D.; Yu, K. M.; Speaks, D. T.; Hemmers, O.; Walukiewicz, W.; Derkachov, G.; Lawniczak-Jablonska, K. Electronic structure of CdO studied by soft X-ray spectroscopy. J. Electron Spectrosc. Relat. Phenom. 2011, 184, 249- 253, 10.1016/j.elspec.2010.09.011
