Stress Induced Modulation of the Structure and Photoelectric Property of Vanadium Oxide Films on Sapphire Substrate

doi:10.15541/jim20180045

Abstract

Abstract:

VO₂ thin films with different thicknesses were deposited on sapphire substrates by pulsed laser deposition. Structure, surface morphologies and photoelectric properties of the films were characterized. The results indicated that the Monoclinic-VO₂ thin films deposited on the sapphire substrates were high quality poly-crystalline stoichiometric with no detectable impurities, and the sheet resistance changed up to 3-4 orders of magnitude and the transmittance at 2500 nm up to 56% across metal-insulator transition (MIT). The optimized integral luminous transmittance (T_lum) and solar regulation rate (∆T_sol) were 43.2% and 8.7%, respectively. The stress on the interface had important influence on the VO₂ thin film, and the photoelectric properties of VO₂ thin films could be regulated by adjusting the film thickness. When the VO₂ film was thinner, the film was subjected to tensile stress, which could significantly reduce the phase-change temperature, and the increase of the carrier concentration as well as carrier mobility accounted for the decrease of electrical resistance across the MIT. While the VO₂ film was thicker, the film was subjected to compressive stress and the phase transition temperature of VO₂ film was close to that of body VO₂. The increase of the carrier concentration accounted almost entirely for the decrease of electrical resistance and the change in mobility had little contribution to the MIT.

Key words: pulsed laser deposition, VO2, stress, photoelectric properties

CLC Number:

O484

ZHANG Cong, KANG Chao-Yang, ZONG Hai-Tao, LI Ming, LIANG Shan-Shan, CAO Guo-Hua. Stress Induced Modulation of the Structure and Photoelectric Property of Vanadium Oxide Films on Sapphire Substrate[J]. Journal of Inorganic Materials, 2018, 33(11): 1225-1231.

Figures/Tables 7

Fig. 1 (a) XRD patterns and (b) amplified XRD patterns in the range of 38°-43° of the VO2 films with different thicknesses deposited on sapphire substrates

Table 1 VO2 (020) peaks position, film strain and the grain sizes of the VO2 films with different thicknesses deposited on sapphire substrates

Thickness /nm	VO₂(020) peaks position/(°)	Film stress /MPa	Grain size /nm
10	39.75	402	13.42
30	39.79	67	14.90
60	39.98	-144	16.27
120	40.02	-161	21.15

Fig. 2 AFM morphologies of VO2 films with different thicknesses deposited on sapphire substrates ^(a) 10 nm; (b) 30 nm; (c) 60 nm; (d) 120 nm

Fig. 3 (a) Transmittance spectra at 25℃ and 90℃ for VO2 films with different thicknesses deposited on sapphire substrates and (b) corresponding variation curves of Tlum(25℃), Tlum(90℃) and ∆Tsol with thickness

Fig. 4 Thermal hysteresis loops of optical transmittance at 2500 nm for VO2 films with different thicknesses deposited on sapphire substrates, with insets showing the corresponding differential curves

Fig. 5 Thermal hysteresis loops of sheet resistance for VO2 films with different thicknesses deposited on sapphire substrates

Fig. 6 Temperature dependent carrier density and mobility curves of VO2 films with different thicknesses deposited on sapphire substrates

References 28

[1]	MORIN F J.Oxides which show a metal-to-insulator transition at the neel temperature.Phys. Rev. Lett., 1959, 3(1): 34-36.
[2]	GOODENOUGH J B.The two components of the crystallographic transition in VO2.J. Solid State Chem., 1971, 3(4): 490-500.
[3]	SUN H J, WANG M H, BIAN J M, et al.Terahertz and metal-insulator transition properties of VO2 film grown on sapphire substrate with MBE.J. Inorg. Mater., 2017, 32(4): 437-442.
[4]	GAO Y F, LUO H J, ZHANG Z T, et al.Nanoceramic VO2 thermochromic smart glass: a review on progress in solution processing.Nano Energy, 2012, 1(2): 221-246.
[5]	HU B, DING Y, CHEN W, et al.External-strain induced insulating phase rransition in VO2 nanobeam and its application as flexible strain sensor.Adv. Mater., 2010, 22(45): 5134-5139.
[6]	ALIEV V S, BORTNIKOV S G,BADMAEVA I A. Anomalous large electrical capacitance of planar microstructures with vanadium dioxide films near the insulator-metal phase transition. Appl. Phys. Lett., 2014, 104(13): 132906-1-4.
[7]	LI W J, JI S D, QIAN K, et al.Preparation and characterization of VO2-BaSO4 composite films with enhanced optical properties in thermochromic field.Ceram. Int., 2015, 41(3): 5049-5056.
[8]	ZHANG Y F, ZHANG J C, ZHANG X Z, et al.Influence of different additives on the synthesis of VO2 polymorphs.Ceram. Int., 2013, 39(7): 8363-8376.
[9]	NAG J, HAGLUND R F.Synthesis of vanadium dioxide thin films and nanoparticles.J. Phys. Condens. Matter, 2008, 20(26): 264016-1-14.
[10]	TAKAMI H, KANKI T, UEDA S, et al. Filling-controlled Mott transition in W-doped VO2. Phys. Rev. B, 2012, 85(20): 205111-1-4 .
[11]	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): 171909-1-3.
[12]	SHEN N, CHEN S, CHEN Z, et al.The synthesis and performance of Zr-doped and W-Zr-codoped VO2 nanoparticles and derived flexible foils.J. Mater. Chem. A, 2014, 2(36): 15087-15093.
[13]	GRANQVIST C G.Transparent conductors as solar energy materials: a panoramic review.Sol. Energ. Mat. Sol. C, 2007, 91(17): 1529-1598.
[14]	ZHANG S X, CHOU J Y, LAUHON L J.Direct correlation of structural domain formation with the metal insulator transition in a VO2 nanobeam.Nano Lett., 2009, 9(12): 4527-4532.
[15]	LAZAROVITS B, KIM K, HAULE K, et al. Effects of strain on the electronic structure of VO2. Phys. Rev. B, 2010, 81(11): 115117-1-9.
[16]	MURAOKA Y, HIROI Z.Metal-insulator transition of VO2 thin films grown on TiO2 (001) and (110) substrates.Appl. Phys. Lett., 2002, 80(4): 583-585.
[17]	HU K, YANG Y J, HONG B, et al.Thickness-dependent anisotropy of metal-insulator transition in (110)-VO2/TiO2 epitaxial thin films.J. Alloys Compd., 2017, 699: 575-580.
[18]	MARTENS K, AETUKURI N, JEONG J, et al. Improved metal-insulator-transition characteristics of ultrathin VO2 epitaxial films by optimized surface preparation of rutile TiO2 substrates. Appl. Phys. Lett., 2014, 104(8): 081918-1-4.
[19]	AETUKURI N B, GRAY A X, DROUARD M, et al.Control of the metal-insulator transition in vanadium dioxide by modifying orbital occupancy.Nat. Phys., 2013, 9(10): 661-666.
[20]	FAN L L, CHEN S, LUO Z L, et al.Strain dynamics of ultrathin VO2 film grown on TiO2 (001) and the associated phase transition modulation.Nano Lett., 2014, 14(7): 4036-4043.
[21]	YANG T H, AGGARWAL R, GUPTA A, et al. Semiconductor- metal transition characteristics of VO2 thin films grown on c- and r-sapphire substrates.J. Appl. Phys., 2010, 107(15): 053514-1-6.
[22]	BIAN J M, WANG M H, SUN H J, et al.Thickness-modulated metal-insulator transition of VO2 film grown on sapphire substrate by MBE.J. Mater. Sci., 2016, 51(13): 6149-6155.
[23]	YANG M M, YANG Y J, HONG B, et al.Surface-growth- mode-induced strain effects on the metal-insulator transition in epitaxial vanadium dioxide thin films.RSC Adv., 2015, 5(98): 80122-80128.
[24]	OHRING M, Materials Science of Thin Films, 2nd ed. Pittsburgh: Academic press, 2001.
[25]	NAGASHIMA K, YANAGIDA T, TANAKA H, et al. Stress relaxation effect on transport properties of strained vanadium dioxide epitaxial thin films.Phys. Rev. B, 2006, 74(17): 172106-1-4.
[26]	CHEN C, CAO C X, LUO H J, et al.VO2-based thermochromic smart window: from energy savings to generation.Chin. Sci. Bull., 2016, 61(15): 1661-1678.
[27]	YAO T, ZHANG X D, SUN Z H, et al. Understanding the nature of the kinetic process in a VO2 metal-insulator transition. Phys. Rev. Lett., 2010, 105(22): 226405-1-4.
[28]	RUZMETOV D, HEIMAN D, CLAFLIN B B, et al. Hall carrier density and magnetoresistance measurements in thin-film vanadium dioxide across the metal-insulator transition. Phys. Rev. B, 2009, 79(15): 153107-1-4.