Atomic layer deposition of vanadium oxides: process and application review

Abstract

Atomic Layer Deposition (ALD) is a method of choice for the growth of highly conformal thin films with accurately controlled thickness on planar and nanostructured surfaces. These advantages make it pivotal for emerging nanotechnology applications. This review sheds light on the current developments on the ALD of vanadium oxide, which, with proper postdeposition treatment yields a variety of functional and smart oxide phases. The application of vanadium oxide coatings in electrochemical energy storage, microelectronics and smart windows are emphasized.

Phase identification of vanadium oxide thin films prepared by atomic layer deposition using X-ray absorption spectroscopy

“…[1][2][3] Among these functional oxides, earth abundant vanadium oxides (VO x ) have garnered increasing attention due to their multiple oxidation states and various local structures, including octahedral, tetrahedral, triclinic, pentagonal bipyramids, and square pyramids. [4][5][6] VO x exhibit remarkable interactions with ions and molecules, superior catalytic activity, suitable intercalation/deintercalation, and strong electron-electron correlations owing to their partially occupied d orbitals, which empower their utilization in a wide range of technological applications. 5,[7][8][9] Although research has mainly focused on VO 2 and V 2 O 5 for numerous applications, including lithium ion batteries, gas sensors, ber optic devices, actuators, data storage devices, switches, smart radiators, and thermochromic smart windows, 3,4,[10][11][12][13] other vanadium oxides with stable stoichiometric and sub-stoichiometric phases have also displayed promising electrochemical properties.…”

“…[4][5][6] VO x exhibit remarkable interactions with ions and molecules, superior catalytic activity, suitable intercalation/deintercalation, and strong electron-electron correlations owing to their partially occupied d orbitals, which empower their utilization in a wide range of technological applications. 5,[7][8][9] Although research has mainly focused on VO 2 and V 2 O 5 for numerous applications, including lithium ion batteries, gas sensors, ber optic devices, actuators, data storage devices, switches, smart radiators, and thermochromic smart windows, 3,4,[10][11][12][13] other vanadium oxides with stable stoichiometric and sub-stoichiometric phases have also displayed promising electrochemical properties. 14,15 Since the chemical and physical properties of VO x vary substantially with the oxidation state of the vanadium cations, it is important to synthesize VO x thin lms with proper stoichiometry for their intended application.…”

“…Several thin lm growth techniques, such as molecular beam epitaxy, 16 sputtering, 17 pulsed laser deposition, 18 electrodeposition, chemical vapor deposition, 19 and atomic layer deposition (ALD) 4 have been used to deposit VO x thin lms with different stoichiometries. ALD is a proven, extraordinarily controllable thin lm deposition technique with great features, including atomically precise lm thicknesses due to self-limiting reactions, uniform and conformal growth over large areas as well as over three-dimensional structures, pinhole free morphologies, and high reproducibility.…”

“…ALD is a proven, extraordinarily controllable thin lm deposition technique with great features, including atomically precise lm thicknesses due to self-limiting reactions, uniform and conformal growth over large areas as well as over three-dimensional structures, pinhole free morphologies, and high reproducibility. 4,20,21 With the ALD process, VO x thin lms have been grown using different metal, metal-organic, and metal-halide precursors as the source material for vanadium and H 2 O, H 2 O 2 , O 3 , molecular O 2 , and O 2 plasma as the oxidizing reactant. 4,14,17,[22][23][24] Among these, vanadyl triisopropoxide (VTIP; V 5+ ) is the most popular vanadium precursor used for the ALD growth process.…”

“…4,20,21 With the ALD process, VO x thin lms have been grown using different metal, metal-organic, and metal-halide precursors as the source material for vanadium and H 2 O, H 2 O 2 , O 3 , molecular O 2 , and O 2 plasma as the oxidizing reactant. 4,14,17,[22][23][24] Among these, vanadyl triisopropoxide (VTIP; V 5+ ) is the most popular vanadium precursor used for the ALD growth process. 4 Conventional ALDgrown VO x thin lms are amorphous in nature, 25,26 except for limited cases where crystalline lms were successfully obtained.…”