Atomic Layer Deposition of V1-xMoxO2 Thin Films, Largely Enhanced

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Comment on “Atomic Layer Deposition of V1-xMoxO2 Thin Films, Largely Enhanced Luminous Transmittance, Solar Modulation” Tianci Chang, Xun Cao, and Ping Jin ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b03424 • Publication Date (Web): 01 Jun 2018 Downloaded from http://pubs.acs.org on June 1, 2018

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ACS Applied Materials & Interfaces

Comment on “Atomic Layer Deposition of V1-xMoxO2 Thin Films, Largely Enhanced Luminous Transmittance, Solar Modulation” Tianci Chang,†,‡,§ Xun Cao,*,†,‡ Ping Jin†,‡, †

⊥

State Key Laboratory of High Performance Ceramics and Superﬁne Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Dingxi 1295, Changning, Shanghai 200050, China

‡

Research Center for Industrial Ceramics, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China

§

University of Chinese Academy of Sciences, Beijing 100049, China

⊥

National Institute of Advanced Industrial Science and Technology (AIST), Moriyama, Nagoya 463-8560, Japan

Corresponding Authors *(X. Cao) E-mail: [email protected]

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Recently, Lv et al. reported Mo-doped VO2 thin films by atomic layer deposition with largely enhanced luminous transmittances and solar modulation.1 In this study, the dopant content of Mo in the V1-xMoxO2 films was controlled by adjusting MoO3 cycle percentage (PMo) (from 2% to 10%) in the ALD process. However, the solar modulation of the V1-xMoxO2 films can reach up to abnormally high values of 19.6% and 23.5% when PMo=5% and 7%, respectively, which is far beyond the acceptable value for VO2-single-layer films. It is well known that luminous transmittance (Tlum ) and solar modulation (ΔTsol ) are the most important indexes of VO2-based thermochromic smart coatings.2 Numerous studies to modify optical properties of VO2-based smart coatings have been carried out by doping,3-18 multilayer design,19-21 composites22-24, and nanostructures25-27. High thermochromic solar modulations larger than 20% have been reported previously, where VO2-based composites have been incorporated with additional organic compounds with additional thermochromic performances, such as ionic liquid complexes and PNIPAm hydrogel, and led to the ultrahigh solar modulations.28-29 Unfortunately, for VO2-based smart coatings without other thermochromic materials, the solar modulation reported by previous work can hardly reach up to ~20%. Doping is a common way to modify the thermochromic performances of VO2 with changing phase transition temperatures and optical properties. Doping of proper cations larger than V4+, such as W6+, Mo6+, and Nb5+,30-32 have been utilized to reduce the phase-transition temperatures. However, previous studies revealed that Mo dopant in VO2 lattice could significantly deteriorate relative ΔTsol , unlike the results showed by Lv et al. with largely enhanced ΔTsol . According to previous studies, Mo-doped VO2 generally shows similar Tlum in semiconducting state and metallic state, even larger Tlum in metallic state than that in semiconducting state, which also have been revealed by the undoped and 2% doped samples with moderate ΔTsol in this article.11-12, 33 However, in this case, Tlum shows large values in semiconducting state than that in metallic state of the samples with 5% and 7% Mo dopants, especially in the near ultraviolet region, which significantly contribute to the largely enhanced ΔTsol of 19.6% and 23.5%, respectively. The authors explained the significant enhancement of solar modulation ability of the samples with 5% and 7% Mo dopants by the porous structures exhibited. Fabricating porous structures is a common 2


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way to improve the luminous transmittances and has been widely reported in previous work. Although enhancement in luminous transmittance can be realized, previous studies on VO2-based films with porous structures can’t reach up to such ultrahigh solar modulation ability and didn’t possess this characteristic in the transmittance spectra.7,

22, 25, 27, 34-37

From the transmittance spectra in this article, an abnormal

phenomenon can be observed: For the undoped and 2% doped samples, relative transmittance spectra show similar absorption edge in the near ultraviolet region both in semiconducting and metallic states; however, when the dopant concentration comes to 5% and 7%, distinct shifts of absorption edges have been shown between semiconducting and metallic state, respectively. Unreasonably, the sample with 7% Mo dopant even indicates a distinct contrast in the near ultraviolet region, which is about 10% at 250 nm by visual inspection. This abnormal phenomenon has never been reported in previous studies, and the author didn’t make a detailed and scientific interpretation. According to the seminal work by Goodenough,38 the electronic structure of semiconducting VO2 and metallic VO2 has been illustrated in Figure 1a and 1b, respectively. Based on the crystal field theory, p-d orbital hybridization occurs between the O 2p orbital and V 3d orbital during the chemical bonding progress. The V 3d t2g orbital divides into dІІ and π* sub-bands, while dІІ and π* is overlapping and partially filled in metallic VO2.38-39 During the transition process from metallic VO2 to semiconducting VO2, further dimerization of V atoms in the otherwise tetragonal lattice, makes the dІІ band split into two parts: the higher dІІ* band is empty and the lower dІІ band is filled, while the π* bands raise above the Fermi level (EF).

38-39

For both semiconducting and metallic state of VO2, there is an absorption at photon energies

about 2.5 eV, which is the gap from the top 2p orbital to the Fermi level.40 By the equation ‫ = ܧ‬ℎ‫= ݒ‬ ℎܿ/ߣ, we can find that this absorption is at around 495 nm and lead to the short-wavelength absorption and the initial yellow color of VO2 both at semiconducting and metallic state.8, 10, 13-14, 16, 41 For doped VO2, the dopants can change electronic structures, lattice parameters and chemical bonds of VO2. However, these changes have similar influences on semiconducting and metallic VO2 and the doped samples exhibit similar absorption edges at temperatures below and above the transition temperature, which has been widely demonstrated and observed in VO2-based films doped by Mg,4, 10, 17-18 F,3, 6, 13 W,7, 9, 15 Mo,11-12 Si,14 Ti,16 et al. In the case of Mo-doped VO2 films, doping of VO2 with Mo6+ or Mo5+ is equivalent to the donor defect 3



Mo୶୚ . The negative charge ionized from the donor defect Mo୶୚ increases the electron density in the film, which causes the Fermi level (EF) shift toward the conduction band.42-43 The widened gap leads to the blue-shift of the absorption edge on both semiconducting and metallic state of the samples and similar absorption edge should be observed in corresponding transmittance spectra. Therefore, we suppose that the transmittance spectra of the samples in this article with 5% and 7% Mo dopants is quite questionable. It is worthy to note that the transition temperature of the Mo-doped VO2, in this case, decreased to 13.5°C and -11.1°C when PMo=5% and 10%, respectively. On the one hand, such low transition temperatures below ambient temperature (25°C) is meaningless for practical applications as smart windows. Previous study on VO2 thin films with heavily Mo doped (larger than 10%) has demonstrated decreased solar modulation ability, when the measurement was carried out at 25°C for semiconducting state and 95°C for metallic state, which is not suitable for application in daily life.11 On the other hand, such low transition temperatures may cause errors during the measurement process. Transition temperatures below ambient temperature should require additional refrigerating equipment for optical measurement of the samples in the semiconducting state. Therefore, the surface of the sample may be attached to extra water layer or ice layer due to the low temperature, which will affect the transmittance properties of the samples. When it comes to the measurement of the metallic state sample, extra water or ice layer will disappear due to the high temperature and not affect the transmittance spectra. We made an optical simulation based on the structure of glass/VO2/ice and glass/VO2/water by Essential Macleod software based on continuous and density mediums,44-46 while corresponding transmittance spectra have been shown in Figure 2a and 2b, respectively. As shown in Figure 2a, for 40 nm VO2 film, the luminous transmittance in the semiconducting state is smaller than that in the metallic state, while the solar modulation is only 6.6%. But when 125 nm ice layer is introduced as the top layer, the sample shows enhanced luminous transmittance in the semiconducting state, which is much larger than that in the metallic state. Meanwhile, relative solar modulation significantly increased to 12.7%. A similar effect also has been observed in Figure 2b, while 125 nm water layer is placed on 40 nm VO2 film and corresponding solar modulation increased from 6.6% to 12.3%. Simulation results have been summarized in Table 1. Therefore, this simulation may explain the

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abnormal data in Lv’s paper, while further experiments and measurement should be carried out for this abnormal and questionable phenomenon. According to the discussion and analysis above, the difference of the absorption edge between the semiconducting and metallic state in the two doped samples (5% and 7%) may be taken into account to investigate the origin reason for this abnormal behaviors. We suppose that the reported high solar modulation (ΔTsol ) of 19.6% and 23.5% is abnormal and could be attributed to experimental errors during the optical measurement process. According to the electronic structures of doped VO2, the sample should show similar absorption edge around the near ultraviolet region both in semiconducting and metallic states. As a suggestion, we recommend the authors to measure optical properties in a high vacuum environment to avoid possible influences on samples. AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected] (X. Cao) Notes The authors declare no competing financial interest. Acknowledgement This study was financially supported by the National Natural Science Foundation of China (No. 51572284), and the “Youth Innovation Promotion Association, Chinese Academy of Sciences” (No. 2018288).

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Figure Captions:

Figure 1. Schematic band structure for metallic (a) and semiconducting (b) VO2. EF denotes Fermi level.

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Figure 2. Optical simulation of 40 nm VO2 films with 125 nm ice layer (a) and 125 nm water layer (b).

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Table 1. Optical properties of samples calculated by optical simulation. Sample

Tlum,lt (%)

Tlum,ht (%)

Tsol,lt (%)

Tsol,ht (%)

ΔTsol (%)

40 nm VO2

36.5

37.7

44.0

37.4

6.6

40 nm VO2/125 nm water

46.9

37.7

50.1

37.4

12.7

40 nm VO2/125 nm ice

46.4

37.7

49.7

37.4

12.3

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References (1) Lv, X.; Cao, Y.; Yan, L.; Li, Y.; Zhang, Y.; Song, L. Atomic Layer Deposition of V1-xMoxO2 Thin Films, Largely Enhanced Luminous Transmittance, Solar Modulation. ACS Appl. Mater. Interfaces 2018, 10 (7), 6601-6607. (2) Chang, T.; Cao, X.; Bao, S.; Ji, S.; Luo, H.; Jin, P. Review on Thermochromic Vanadium Dioxide based Smart Coatings: From Lab to Commercial Application. Adv. Manuf. 2018, 6 (1), 1-19. (3) Burkhardt, W.; Christmann, T.; Franke, S.; Kriegseis, W.; Meister, D.; Meyer, B. K.; Niessner, W.; Schalch, D.; Scharmann, A. Tungsten and Fluorine Co-Doping of VO2 Films. Thin Solid Films 2002, 402 (1-2), 226-231. (4) Panagopoulou, M.; Gagaoudakis, E.; Boukos, N.; Aperathitis, E.; Kiriakidis, G.; Tsoukalas, D.; Raptis, Y. S. Thermochromic Performance of Mg-Doped VO2 Thin Films on functional substrates for glazing applications. Sol. Energy Mater. Sol. Cells 2016, 157, 1004-1010. (5) Xu, Y.; Huang, W.; Shi, Q.; Zhang, Y.; Song, L.; Zhang, Y. Synthesis and Properties of Mo and W Ions Co-Doped Porous Nano-Structured VO2 films by Sol-Gel Process. J. Sol-Gel Sci. Technol. 2012, 64 (2), 493-499. (6) Burkhardt, W.; Christmann, T.; Meyer, B. K.; Niessner, W.; Schalch, D.; Scharmann, A. W- and F-Doped VO2 Films Studied by Photoelectron Spectrometry. Thin Solid Films 1999, 345 (2), 229-235. (7) Hu, L.; Tao, H.; Chen, G.; Pan, R.; Wan, M.; Xiong, D.; Zhao, X. Porous W-Doped VO2 Films with Simultaneously Enhanced Visible Transparency and Thermochromic Properties. J. Sol-Gel Sci. Technol. 2016, 77 (1), 85-93. (8) Dietrich, M. K.; Kramm, B. G.; Becker, M.; Meyer, B. K.; Polity, A.; Klar, P. J. Influence of Doping with Alkaline Earth Metals on the Optical Properties of Thermochromic VO2. J. Appl. Phys. 2015, 117 (18), 185301. (9) Liang, Z.; Zhao, L.; Meng, W.; Zhong, C.; Wei, S.; Dong, B.; Xu, Z.; Wan, L.; Wang, S. Tungsten-Doped Vanadium Dioxide Thin Films as Smart Windows with Self-Cleaning and Energy-Saving Functions. J. Alloys Compd. 2017, 694, 124-131. (10) Zhou, J.; Gao, Y.; Liu, X.; Chen, Z.; Dai, L.; Cao, C.; Luo, H.; Kanahira, M.; Sun, C.; Yan, L. Mg-Doped VO2 Nanoparticles:

Hydrothermal

Synthesis,

Enhanced

Visible

Transmittance

and

Decreased

Metal-Insulator Transition Temperature. Phys. Chem. Chem. Phys. 2013, 15 (20), 7505-7511. (11) Liu, S.; Fang, H.; Su, Y.; Hsieh, J. Metal–Insulator Transition Characteristics of Mo- and Mn-Doped VO2 Films Fabricated by Magnetron Cosputtering Technique. Jpn. J. Appl. Phys. 2014, 53 (6), 063201. (12) Zhao, L.; Miao, L.; Liu, C.; Li, C.; Cheng, H. Facile Solution-Grown Mo-Doped Vanadium Dioxide Thermochromic Films with Decreased Phase Transition Temperature and Narrowed Hysteresis Loop Width. Mater. Sci. Forum 2014, 787, 23-30. (13) Dai, L.; Chen, S.; Liu, J.; Gao, Y.; Zhou, J.; Chen, Z.; Cao, C.; Luo, H.; Kanehira, M. F-Doped VO2 Nanoparticles for Thermochromic Energy-Saving Foils with Modified Color and Enhanced Solar-Heat Shielding Ability. Phys. Chem. Chem. Phys. 2013, 15 (28), 11723-11729. (14) Wu, X.; Wu, Z.; Zhang, H.; Niu, R.; He, Q.; Ji, C.; Wang, J.; Jiang, Y. Enhancement of VO2 Thermochromic Properties by Si Doping. Surf. Coat. Technol. 2015, 276, 248-253. (15) Wang, N.; Liu, S.; Zeng, X. T.; Magdassi, S.; Long, Y. Mg/W-Codoped Vanadium Dioxide Thin Films with Enhanced Visible Transmittance and Low Phase Transition Temperature. J. Mater. Chem. C 2015, 3 9



(26), 6771-6777. (16) Du, J.; Gao, Y.; Luo, H.; Kang, L.; Zhang, Z.; Chen, Z.; Cao, C. Significant Changes in Phase-Transition Hysteresis for Ti-Doped VO2 Films Prepared by Polymer-Assisted Deposition. Sol. Energy Mater. Sol. Cells 2011, 95 (2), 469-475. (17) Li, S.-Y.; Mlyuka, N. R.; Primetzhofer, D.; Hallén, A.; Possnert, G.; Niklasson, G. A.; Granqvist, C. G. Bandgap Widening in Thermochromic Mg-Doped VO2 Thin Films: Quantitative Data Based on Optical Absorption. Appl. Phys. Lett. 2013, 103 (16), 161907. (18) Mlyuka, N. R.; Niklasson, G. A.; Granqvist, C. G. Mg Doping of Thermochromic VO2 Films Enhances the Optical Transmittance and Decreases the Metal-Insulator Transition Temperature. Appl. Phys. Lett. 2009, 95 (17), 171909. (19) Chang, T.; Cao, X.; Dedon, L.; Long, S.; Huang, A.; Shao, Z.; Li, N.; Luo, H.; Jin, P. Optical Design and Stability Study for Ultrahigh-Performance and Long-Lived Vanadium Dioxide-Based Thermochromic Coatings. Nano Energy 2018, 44, 256-264. (20) Chang, T.; Cao, X.; Li, N.; Long, S.; Gao, X.; Dedon, L. R.; Sun, G.; Luo, H.; Jin, P. Facile and Low-Temperature Fabrication of Thermochromic Cr2O3/VO2 Smart Coatings: Enhanced Solar Modulation Ability, High Luminous Transmittance and UV-Shielding Function. ACS Appl. Mater. Interfaces 2017, 9 (31), 26029-26037. (21) Zheng, J.; Bao, S.; Jin, P. TiO2(R)/VO2(M)/TiO2(A) Multilayer Film as Smart Window: Combination of Energy-saving, Antifogging and Self-cleaning Functions. Nano Energy 2015, 11, 136-145. (22) Liu, C.; Cao, X.; Kamyshny, A.; Law, J. Y.; Magdassi, S.; Long, Y. VO2/Si-Al Gel Nanocomposite Thermochromic Smart Foils: Largely Enhanced Luminous Transmittance and Solar Modulation. J. Colloid Interface Sci. 2014, 427, 49-53. (23) Cao, Z.; Lu, Y.; Xiao, X.; Zhan, Y.; Cheng, H.; Xu, G. Tunable Simultaneously Visible-light and Near-infrared Transmittance for VO2/SiO2 Composite Films to Enhance Thermochromic Properties. Mater. Lett. 2017, 209, 609-612. (24) Li, W.; Ji, S.; Qian, K.; Jin, P. Preparation and Characterization of VO2–BaSO4 Composite Films with Enhanced Optical Properties in Thermochromic Field. Ceram. Int. 2015, 41 (3), 5049-5056. (25) Lu, Q.; Liu, C.; Wang, N.; Magdassi, S.; Mandler, D.; Long, Y. Periodic Micro-Patterned VO2 Thermochromic Films by Mesh Printing. J. Mater. Chem. C 2016, 4 (36), 8385-8391. (26) Ke, Y.; Balin, I.; Wang, N.; Lu, Q.; Tok, A. I.; White, T. J.; Magdassi, S.; Abdulhalim, I.; Long, Y. Two-Dimensional SiO2/VO2 Photonic Crystals with Statically Visible and Dynamically Infrared Modulated for Smart Window Deployment. ACS Appl. Mater. Interfaces 2016, 8 (48), 33112-33120. (27) Kang, L.; Gao, Y.; Luo, H.; Chen, Z.; Du, J.; Zhang, Z. Nanoporous Thermochromic VO2 Films with Low Optical Constants, Enhanced Luminous Transmittance and Thermochromic Properties. ACS Appl. Mater. Interfaces 2011, 3 (2), 135-138. (28) Zhu, J.; Huang, A.; Ma, H.; Ma, Y.; Tong, K.; Ji, S.; Bao, S.; Cao, X.; Jin, P. Composite Film of Vanadium Dioxide Nanoparticles and Ionic Liquid-Nickel-Chlorine Complexes with Excellent Visible Thermochromic Performance. ACS Appl. Mater. Interfaces 2016, 8 (43), 29742-29748. (29) Zhou, Y.; Cai, Y.; Hu, X.; Long, Y. VO2/hydrogel Hybrid Nanothermochromic Material with Ultra-high Solar Modulation and Luminous Transmission. J. Mater. Chem. A 2015, 3 (3), 1121-1126. (30) Zhu, J.; Zhou, Y.; Wang, B.; Zheng, J.; Ji, S.; Yao, H.; Luo, H.; Jin, P. Vanadium Dioxide 10


Page 10 of 12

Page 11 of 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Nanoparticle-Based Thermochromic Smart Coating: High Luminous Transmittance, Excellent Solar Regulation Efficiency, and Near Room Temperature Phase Transition. ACS Appl. Mater. Interfaces 2015, 7 (50), 27796-27803. (31) Lv, W.; Huang, D.; Chen, Y.; Qiu, Q.; Luo, Z. Synthesis and Characterization of Mo–W Co-Doped VO2(R) Nano-powders by the Microwave-Assisted Hydrothermal Method. Ceram. Int. 2014, 40 (8), 12661-12668. (32) Piccirillo, C.; Binions, R.; Parkin, I. P. Nb-Doped VO2 Thin Films Prepared by Aerosol-Assisted Chemical Vapour Deposition. Eur. J. Inorg. Chem. 2007, 2007 (25), 4050-4055. (33) Jin, P.; Tanemura, S. V1−xMoxO2 Thermochromic Films Deposited by Reactive Magnetron Sputtering. Thin Solid Films 1996, 281-282, 239-242. (34) Wu, S.; Tian, S.; Liu, B.; Tao, H.; Zhao, X.; Palgrave, R. G.; Sankar, G.; Parkin, I. P. Facile Synthesis of Mesoporous VO2 Nanocrystals by a Cotton-Template Method and Their Enhanced Thermochromic Properties. Sol. Energy Mater. Sol. Cells 2018, 176, 427-434. (35) Cao, X.; Wang, N.; Law, J. Y.; Loo, S. C.; Magdassi, S.; Long, Y. Nanoporous Thermochromic VO2(M) Thin Films: Controlled Porosity, Largely Enhanced Luminous Transmittance and Solar Modulating Ability. Langmuir 2014, 30 (6), 1710-1715. (36) Zhang, J.; Wang, J.; Yang, C.; Jia, H.; Cui, X.; Zhao, S.; Xu, Y. Mesoporous SiO2/VO2 Double-layer Thermochromic Coating with Improved Visible Transmittance for Smart Window. Sol. Energy Mater. Sol. Cells 2017, 162, 134-141. (37) Chen, R.; Miao, L.; Cheng, H. L.; Nishibori, E.; Liu, C. Y.; Asaka, T.; Iwamoto, Y.; Takata, M.; Tanemura, S. One-Step Hydrothermal Synthesis of V1-xWxO2 (M/R) Nanorods with Superior Doping Efficiency and Thermochromic Properties. J. Mater. Chem. A 2015, 3 (7), 3726-3738. (38) Goodenough, J. B. The Two Components of the Crystallographic Transition in VO2. J. Solid State Chem. 1971, 3 (4), 490-500. (39) Ahuja, R.; Granqvist, C. G.; Hermansson, K.; Niklasson, G. A.; Scheicher, R. H. Optical Properties of Mg-Doped VO2: Absorption Measurements and Hybrid Functional Calculations. Appl Phys Lett 2012, 101 (20), 201902. (40) Verleur, H. W.; Barker, A. S.; Berglund, C. N. Optical Properties of VO2 between 0.25 and 5 eV. Phys. Rev. 1968, 172 (3), 788-798. (41) Wang, N.; Duchamp, M.; Dunin-Borkowski, R. E.; Liu, S.; Zeng, X.; Cao, X.; Long, Y. Terbium-Doped VO2 Thin Films: Reduced Phase Transition Temperature and Largely Enhanced Luminous Transmittance. Langmuir 2016, 32 (3), 759-764. (42) Mai, L. Q.; Hu, B.; Hu, T.; Chen, W.; Gu, E. D. Electrical Property of Mo-Doped VO2 Nanowire Array Film by Melting−Quenching Sol−Gel Method. J. Phys. Chem. B 2006, 110 (39), 19083-19086. (43) Xu, S.; Ma, H.; Dai, S.; Jiang, Z. Study on Optical and Electrical Switching Properties and Phase 6+

Transition Mechanism of Mo -Doped Vanadium Dioxide Thin Films. J. Mater. Sci. 2004, 39 (2), 489-493. (44) Loka, C.; Moon, S. W.; Choi, Y.; Lee, K. High Transparent and Conductive TiO2/Ag/TiO2 Multilayer Electrode Films Deposited on Sapphire Substrate. Electron. Mater. Lett. 2018, 14 (2), 125-132. (45) Kim, Y. T.; Cho, J. Y.; Heo, J. Formation of Antireflection Structures for Ailicon in Near-Infrared Region using AlOx/TiOx Bilayer and SiNx Single-Layer. J. Non-Cryst. Solids 2018, 489, 22-26. 11



(46) Kovacs, A.; Mescheder, U. Optical Characterization of Pore Filling in Mesoporous Multilayers by Ultrathin Atomic Layer Deposited Hafnium Dioxide. J. Vac. Sci. Technol., A 2018, 36 (3), 031508.

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Atomic Layer Deposition of V1-xMoxO2 Thin Films, Largely Enhanced

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