Preparation and modification of VO₂thin film on R-sapphire substrate by rapid thermal process

Abstract

The VO 2 thin film with high performance of metal-insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO 2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO 2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a followup RTP modification in nitrogen atmosphere. The crystallization and components of VO 2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-• C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively.

Wafer-scale growth of VO2 thin films using a combinatorial approach

“…A representative set of data was compiled and is shown in Fig. 6b to allow for a direct comparison with bulk single crystals 46 47 48 49 50 51 52 as well as VO 2 thin films grown by deposition techniques such as PLD 21 41 53 54 55 56 , metalorganic chemical vapour deposition 57 58 , MBE 27 and sputtering 8 23 25 59 60 61 62 . The selection criteria were either single crystals in case of bulk material, or completely relaxed VO 2 films grown on sapphire samples, that is, with thicknesses exceeding the critical film thickness of 20 nm (ref.…”

“…Properties of VO 2 films on Al 2 O 3 substrate grown by PLD were taken from refs 21 , 42 , 52 , 53 , 54 , 55 , 56 , 57 , MOCVD from refs 58 , 59 , MBE from ref. 27 and sputtering from refs 8 , 23 , 25 , 60 , 61 , 62 , 63 .…”

Opportunities in vanadium-based strongly correlated electron systems

“…Growth at high substrate temperature to overcome the kinetic barrier to oxidation is not an option for two reasons: (1) the rapid interdiffusion of VO 2 into the underlying substrates [50,52,54] and (2) if the entire film is oxidized to V 2 O 5 , it will all evaporate due to the high vapor pressure of V 2 O 5 . [55] Despite the many challenges involved in the growth of VO 2 films, significant advances have been achieved in its deposition using PLD, [42,[56][57][58][59][60][61][62][63] MBE, [52,53,64,65] sputtering, [66][67][68][69][70][71][72][73] electronbeam deposition, [74] ion-beam depostion, [75] metalorganic [48,49] (c) Resistivity versus temperature for various V-O phases, with a MIT at different temperatures. While V 2 O 3 exhibits the largest change in resistivity over eight orders of magnitude, but below room temperature, VO 2 has the largest resistivity ratio above room temperature of about five orders of magnitude.…”

Surface plasmon-enhanced dual-band infrared absorber for ${\mathrm{VO}}_{{\boldsymbol{x}}}$-based microbolometer application

“…[2] A thin film of the mixed oxides sputtered on an Si 3 N 4 microbridge substrate is originally developed at Honeywell. [1,3] VO x based micrometers with better responsivity [4] and lower noise factor [5] are widely used in missile warning system and military equipment. Dual band infrared detector has always been a keen interest for many applications with more superior performance [6,7] and wider working band.…”