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Non-hydrogenated germanium carbide (Ge1−xCx) films were prepared by magnetron co-sputtering method in a discharge of Ar. The surface topography, chemical bonding configurations and hardness were characterized by means of atomic force microscopy, X-ray photoelectron spectroscopy (XPS) and nanoindentation technique. The substrate temperature (Ts ) exhibited important influence on the film surface topography. With the increase of Ts , the films became smoother owing to stronger diffusion. The film mass density varied between 4.40g/cm3 and 4.47g/cm3 depending on Ts . A progressive densification of the film microstructure occurred with Ts increasing. The XPS results showed that both the content of the Ge Ge bond and the content of the C Ge bond in the films increased as Ts increased. The relationship between the chemical bonding and the mechanical properties of the Ge1−xCx films was also explored. It showed that the hardness of the films increases from 7.47GPa to 11.48GPa as Ts increases from 200°C to 700°C. Therefore, increasing the substrate temperature led to a more dense and hard Ge1−xCx film. [ABSTRACT FROM AUTHOR]

Abstract: A series of yttrium oxide films has been fabricated on Si (100) wafers by different substrate temperatures based on reactive magnetron sputtering technology. And the evolution of composition, microstructure and optical properties of Y2O3 films has been investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and spectroscopic ellipsometry (SE). It is shown that stoichiometric Y2O3 with much strong Y O bond and cubic nanophase with larger size notably enhance the optical properties, especially refractive index. At low substrate temperature, the composition of Y2O3 films has nonstoichiometry feature accompanying with much physisorbed oxygen (Oδ) compared with these at high temperature. Increasing substrate temperature promotes the formation of Y O bonds, approaching the stoichiometry with lower Oδ content. The film commences crystallizing at room temperature, and transformation of crystalline phase from monoclinic to cubic occurs, along with preferred (111) orientation and large grain as temperature increases. The results facilitate clear relationship between the characterizations of Y2O3 film and growth parameters, also, it can be realized that adjustment of optical constants of Y2O3 films in a large range having the aid of substrate temperature to obtain desirable composition and structure for optical applications. [Copyright &y& Elsevier]

Abstract: In this study, alumina thin films were deposited on Si (100) substrates by reactive magnetron sputtering in an Ar–O2 atmosphere. The resputtering technique without any separated ion source was applied, as well as various substrate biases and deposition temperatures. Suitable oxygen/argon gas flow rate ratio was obtained to deposit stoichiometric Al2O3 films. As investigated by grazing incidence X-ray diffraction (GIXRD) and nanohardness measurements, the amorphous characteristics and hardness values of alumina films aren''t altered with the various substrate biases up to −120V at the temperatures up to 600°C. The microstructure of alumina films with thin crystalline Al2O3 layer between the amorphous layers was achieved with the resputtering technique at elevated temperatures (≤300°C). This suggests that the reactive magnetron sputtering with the resputtering technique is a simple and effective method of preparing crystalline alumina films at relatively low temperature. The existence of thin crystalline Al2O3 layers between the amorphous layers makes the film harder than the amorphous films. In general, increasing the deposition temperature with the resputtering technique increased the hardness of the films, thus the crystalline-volume fraction of the films. However, the hardness was not a monotonic function of the deposition temperature. [Copyright &y& Elsevier]

Yttrium oxide films were prepared on silicon wafers by reactive magnetron sputtering at different oxygen flow rates to investigate the microstructure and optical properties for desirable planar optical waveguiding applications. Under the different conditions of target surface, the deposition rate, structure, and optical properties have great changes. The deposition rate increases to the maximum, and then monotonically decreases. Oxygen content in films increases and the composition of films transforms from stoichiometry to an oxygen-rich state. YO films grow with the (222) preferred growth orientation at low oxygen flow rate, and then turn into the (622) orientation; the microstructure evolves from crystal structure to amorphous state as oxygen flow rate increases from 2 to 12 sccm. Sufficient oxygen makes films low-order structure and oxygen-rich films have poor crystallinity. Very smooth film has been obtained at oxygen flow rate of 12 sccm. The refractive index can be greatly modulated by the oxygen-content factor. It is convincing that the controllable structure and optical properties of YO films can be achieved by adjustment the oxygen flow rate for desired optical design and applications. [ABSTRACT FROM AUTHOR]

Transparent conducting oxide films are usually several 100-nm thick to achieve the required low sheet resistance. In this study, we show that the filtered cathodic arc technique produces high-quality low-cost ZnO:Al material for comparably smaller thicknesses than achieved by magnetron sputtering, making arc deposition a promising choice for applications requiring films less than 100-nm thick. A mean surface roughness less than 1 nm is observed for ZnO:Al films less than 100-nm thick, and 35-nm-thick ZnO:Al films exhibit Hall mobility of 28 cm2/Vs and a low resistivity of 6.5 × 10−4 Ωcm. Resistivity as low as 5.2 × 10−4 Ωcm and mobility as high as 43.5 cm2/Vs are obtained for 135-nm films. [ABSTRACT FROM PUBLISHER]

Abstract: Yttrium oxide (Y2O3) is a promising ceramic material for electronic and optical applications due to its excellent properties. The purpose of this study is to characterize the effects of deposition parameters on the structure and composition of Y2O3 films. The films are grown on Si substrates by reactive magnetron sputtering at different substrate temperatures and oxygen pressures. The composition and structure of the films are studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. It is shown that the Y2O3 films deposited by reactive magnetron sputtering are mainly cubic phase and polycrystalline. The films are composed of Y–O, Y–O–Si, and Si–O bonds. Increasing substrate temperature induces the monoclinic to cubic phase transition and results in the formation of oxygen vacancies in the film. The preferred growth orientation of Y2O3 film is the (110) plane at low temperature, and it changes to the (111) plane at high temperature. The low temperature is preferable for the formation of Y–O bonds. The oxygen pressure influences on the concentration of Y–O bonds significantly. An optimal oxygen partial pressure for the formation of Y–O bonds exists during the film deposition. In addition, the deposited Y2O3 films exhibit excellent mechanical properties. [Copyright &y& Elsevier]

Abstract: In this paper, the resputtering technique without separated ion sources was used to improve the crystallization of alumina films during preparation at low temperature using reactive magnetron sputtering. The effects of the novel resputtering technique on the microstructural, mechanical and optical properties of alumina films were investigated by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD), nanohardness measurements and Ultra/visible spectrometer. The AFM diagram indicated that the low root-mean-square (rms) roughness values of alumina films increased from 0.8nm to 5.8nm by the resputtering technique. The GIXRD patterns showed that with the resputtering technique, alumina thin films transformed from the amorphous phase into crystalline phase. The nanohardness of the films increased from 13.6GPa to 15.6GPa by the resputtering technique, which was only slightly smaller than that of the crystalline alumina films subjected to a post-annealing at 950°C, about 16.6GPa. Additionally, the crystalline alumina films deposited with resputtering technique also display good optical properties with higher refractive index, as compared to the amorphous films. The results suggest that the reactive magnetron sputtering with the resputtering technique is a simple, cheap and effective method of preparing crystalline alumina films at low temperature. [Copyright &y& Elsevier]

Interface engineering has emerged as a fertile and efficacious approach to turn functional properties in the field of film systems. In this work, the interfacial properties of sputtered yttrium oxide films on zinc sulfide substrate (Y 2 O 3 /ZnS) were analyzed by transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS) depth profile and nano-scratch measurement. An interface layer with the depth of 20 nm between Y 2 O 3 film and ZnS substrate was directly observed by TEM. Under different film growth conditions, although the interfacial features including interfacial width and composition distribution exhibit similar behavior, it is found that higher cohesive strength is obtained under a special substrate bias voltage of −160 V at low substrate temperature. Such an enhanced mechanical property can be understood by the role of physisorbed oxygen in the interfacial region, in which less physisorbed oxygen with van der Waals bonds leads to a strong adhesion. Our results provide a favorable strategy to achieve strong adhesion between oxide and sulfide at low temperature, which are urgent in future micro-electric applications. [ABSTRACT FROM AUTHOR]

In order to understand the growth behavior of yttrium oxide films driven by thermodynamics and kinetics, two fundamental growth parameters, substrate heating and biasing, were investigated to control film structure and properties comprehensively. We observed two distinct areas, normal deposition area (area 1) and abnormal deposition area (etching area, area 2) at different substrate bias voltages regardless of the substrate temperature. X-ray diffraction (XRD) results show that heating promotes cubic phase formation, whereas ion bombardment induces monoclinic phase growth. Atomic force microscopy (AFM) measurements exhibit that the ions slightly enlarge the surface islands in area 1, whereas they flatten and smoothen the surface in area 2. X-ray photoelectron spectroscopy (XPS) results demonstrate that high temperature suppresses the physisorbed oxygen, and the ion bombardment favorably selects oxygen etching in area 1, causing excess oxygen vacancies. This selectivity almost disappears in area 2. Furthermore, the refractive index and band gap can be enhanced by both substrate temperature and bias voltage. The surface wettability of films can be modulated by the surface chemical composition. [ABSTRACT FROM AUTHOR]

Herein, highly transparent and conductive In 2 O 3 films were deposited by reactive high power impulse magnetron sputtering from a metal target without thermal assistance. Film deposition was performed at room temperature using oxygen flow rates selected based on target voltage hysteresis, and the obtained films were compared in terms of structure and electrical/optical properties. Notably, the use of high plasma density, peak power, and ionization efficiency resulted in the formation of highly crystalline films featuring a small grain size and a columnar structure with a preferred orientation. The minimal carrier concentration of 1.6 × 1021 cm−3 was observed for films deposited in metallic mode; the carrier mobility of these films increased from 23 to 51 cm2 V−1 s−1 as the oxygen flow rate increased from 7 to 10 sccm. Moreover, the oxygen flow rate significantly affected the conductivity of In 2 O 3 films, which ranged from semiconductor-like to insulator. The visible-light transmittance of In 2 O 3 films exceeded 85% when oxygen flow rate larger than 7sccm. The absorption edge of as-prepared films was located close to 350 nm and shifted to lower wavelengths with increasing oxygen flow rate, which was explained by the Burstein–Moss effect. The infrared transmittance of In 2 O 3 films was strongly dependent on the deposition mode. In agreement with Drude's theory, films deposited in transition mode at room temperature were highly transparent and conductive, which was ascribed to the use of controlled In:O ratios, whereas films deposited in other modes were shown to exhibit either excellent conductivity (metallic mode) or good optical transmittance (poisoning mode). Image 1 [ABSTRACT FROM AUTHOR]

• A new P-type transparent conductive LaSe 2 film with excellent photoelectric properties is found. • A novel two-step method is used to prepare LaSe 2 film. • Effect of annealing time on their photoelectric properties is investigated. • Results indicate that the best annealing time is 2 h. LaSe 2 films were prepared on sapphire (0001) substrates by combining magnetron sputtering and selenized annealing. The influence of selenized annealing time on the structures and photoelectric properties of the thin films were investigated using glancing incident X-ray diffraction, fourier transform infrared spectrometry and Hall effect measurements. The results showed that the film had a perfect monoclinic structure and a smooth surface morphology. The average transmittance in the mid-infrared range was greater than 55%, and the highest was 65%. The LaSe 2 films had a higher carrier concentration (∼1019 cm−3) and conductivity (∼1.9 S/cm) than those of other P-type transparent conductive films, which showed that LaSe 2 was a potential new P-type material. [ABSTRACT FROM AUTHOR]

Abstract The hydrated magnesium-carbon films fabricated in this study demonstrated that grain growth and crystallinity modification by substrate temperature treatment crystallization produce films with fewer internal imperfections. This results in high mobility of the solution-deposited hydrated magnesium-carbon electrical conductance, with a corresponding dramatic harmonious transmittance in the infrared range. An investigation of the hydrated magnesium-carbon films shows that the temperature treatment dramatically improves the electron mobility and decreases the carrier concentration, which in turn simultaneously increases the conductivity and transparency. The hydrated magnesium-carbon films exhibit a mobility of up to 85.2 cm2/(V·s) and the resistivity declines rapidly to 1.72 × 10−2 Ω·cm. The transmittance of the visible spectrum increased to 90%. Although the conductivity of hydrated magnesium-carbon films is not prominent comparing to the conventional and widely-used n-type TCO materials, e.g. ITO, the films also showed excellent optical properties, which can be attributed to their low bond energy, with the infrared transmittance of the films being greater than 70% for a plasma wavelength of approximately 10 μm. Graphical abstract Unlabelled Image Highlights • The hydrated magnesium-carbon films are the non-oxide-type transparent electronic material. • The plasma wavelength of hydrated magnesium-carbon films was approximate 10 μm. • Discussed the effects of the carrier concentration and mobility on the photoelectrical properties. • Studied on effects of the substrate temperature on the photoelectrical properties. [ABSTRACT FROM AUTHOR]

Abstract Transparent electronic technology has many urgent optoelectronic device applications. A key component of plasmonic materials in conventional semiconductors is the wide band gap of oxide thin films. Although transparent electronic materials have been developed for visible and near-infrared wavelengths, systems incorporating mid-infrared and far-infrared spectra are difficult to achieve. In this study, hydrated magnesium-carbon films, a new type of non-oxide transparent conductive thin films with a magnesium hydroxide structure, were generated using the three-step method. After annealing treatment, larger crystals in the thin films typically exhibited superior film resistivity, with conductivity values of approximately 8.63 × 10−3 Ω m. Due to the free electron concentration was not more than 1020 cm−3, the films demonstrated excellent optical properties, with plasma wavelength values of approximately 8 μm for infrared transmittance above 70%. After annealing, due to the Moss-Burstein (M-B) effect, the visible light transmittance was greater than 85% and the optical bandgap shifted towards the blue region. In addition, the influences of the sputtering power of the carbon target on the properties of hydrated magnesium-carbon film were also discussed in this paper. Graphical abstract Image 1 Highlights • We prepare hydrated magnesium-carbon films using the three-step method. • We analyze the effect of annealing on structural, electrical, and optical features. • Annealing leads to crystal growth, superior film resistivity, and good conductivity. • Films exhibit excellent optical properties, particularly for far-infrared ranges. • The films can replace TCO in the application of optical-electronic devices. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel two-step method is developed to grow 2D Mg(OH) 2 nanoflakes. • The proposed method is environmentally benign. • The method does not require catalysts or harsh acid-base conditions. • The Mg(OH) 2 films had a crystalline hexagonal structure is dominant. • The water contact angle of 139° showed the good hydrophobicity of the film. Abstract A novel and environmentally benign two-step method has been developed to grow 2D magnesium hydroxide (Mg(OH) 2) nanoflakes. Our method relies on the deposition of Mg films by magnetron sputtering, followed by reaction with water vapor, and does not require any catalyst or harsh acid-base conditions. The 2D nanoflake surface morphology with a crystalline hexagonal structure was dominant on the Mg(OH) 2 films. The water contact angle on the film was ∼139°, which testified the good hydrophobicity of Mg(OH) 2 films due to the nanoflake surface. The self-cleaning effect of contaminant particles on hydrophobic Mg(OH) 2 films was analyzed. Compared with other preparation methods, this two-step method is more efficient, cleaner, and simpler, which make it suitable for complex or large-area substrate surfaces. In addition, this method can be applied to other metal hydroxides or oxides. [ABSTRACT FROM AUTHOR]

Abstract A special design of the structure of magnetron sputtering equipment is proposed to facilitate the deposition of uniform films on non-planar surfaces with a small target. A guide rail is used to adjust the inclination of the target in combination with the rotation and vertical movement of the substrate holder to achieve step-by-step coating. A calculation model is proposed to simulate the effects of target-substrate distance, experiment condition coefficient, magnetron racetrack area, and staying time on the film deposition rate and thickness distribution. The relationship between the experimental parameters and theoretical tolerance values was also established in this design. Uniform films were deposited on a substrate having a diameter and height of 160 mm with a 2 in. Ti target. Measurement results show that the relative thickness distribution is less than ±3%, which agreed well with the calculation, demonstrating that the model is applicable for depositing uniform films on large convex surfaces. In addition, this calculation model provided a possible method to deposit uniform films on other surface sizes and types. Highlights • A model proposed to deposit uniform films on convex surfaces without masks. • Distribution error could be predicted under different parameters. • Uniform films on convex surface with 3% error obtained. [ABSTRACT FROM AUTHOR]

As an inevitable existence in semiconductor heterostructures, interfacial states have a non-negligible impact on the performance of heterojunction-based optoelectronic devices. Here, we develop high-performance photodiodes based on heterointerface-engineered type II SnO 2 /boron-doped diamond (BDD) heterojunctions. We modulate the type of the interfacial states of SnO 2 /BDD heterojunctions by changing the partial pressure of oxygen during the process of SnO 2 deposition by RF magnetron sputtering. As a result, backward rectifying, Zener, and forward rectifying diodes are obtained. The diversity of the diode characteristics is related to the carrier tunneling and avalanche multiplication effects. In addition, the I–V curve of the Zener diode has a negative differential resistance precursor under UV light irradiation. The photogenerated holes in the forward rectifier diode are easily trapped at the heterointerface during transmission. Zener and forward rectifier diodes can output positive and negative photocurrents (i.e., binary photoresponse) under on/off periodic light illumination owing to photovoltaic and pyro-phototronic effects. These results reveal the potential of SnO 2 /BDD heterojunctions in the field of optical logic computing devices. • Three SnO 2 /BDD heterojunction photodiodes with different types of interfacial states were fabricated. • All three devices can achieve binary photoresponse output, but have diverse diode characteristics in the dark. • The photoresponse spectrum of the device with weak donor-type interfacial states can be broadened to visible band. • The binary photoresponse mechanism of three devices are explained by photovoltaic and pyro-phototronic effects. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of deposition conditions on the properties of yttrium oxide thin films. The paper focuses on the texture, optical and mechanical properties. With this objective, a series of yttrium oxide thin films with different thicknesses were deposited by direct current (DC) unbalanced reactive magnetron sputtering at high and low pumping speed. By changing the oxygen flow, depositions were performed in the three characteristic deposition modes for reactive magnetron sputtering, i.e., metallic, transition and poisoned mode. By using an oxygen flow directed to the substrate, full oxidation of the samples, as shown by X-ray photoelectron spectroscopy (XPS), in the three modes is obtained. Crystallographic characterization by X-ray diffraction (XRD) shows that films crystallize in the cubic phase with a strong (222) out-of-plane orientation at low oxygen flow. As the oxygen flow increases a mixture of cubic and monoclinic phase is obtained. In poisoned mode, the films consist of the cubic phase with preferred (420) orientation. Scanning electron microscopy (SEM) cross sections show, with increasing oxygen flow, a loss of the columnar structure. As the oxygen flow rates increase through the metallic, transition, and the poisoned mode, the grain size becomes gradually smaller. An overview diagram of all experimental results uncovers that the textural changes are closely linked to the oxygen partial pressure rather than the oxygen flow. The optical properties of films were investigated by spectroscopic ellipsometry (SE). The films with a columnar structure demonstrate superior hardness and modulus as well as the high plasticity. [ABSTRACT FROM AUTHOR]

Materials for infrared domes are required to maintain good properties in harsh environments including mechanical strength, optical transmittance over a wide range of wavelengths and low emissivity. The purpose of this work is to sputter Y 2 O 3 film onto a sapphire substrate by a radio frequency magnetron sputtering method and investigate the structural and thermal radiation properties of the films. In addition, the apparent emissivity of the coated sapphire is simulated for different film thicknesses at different temperatures. The experimental results show that the surface of the Y 2 O 3 film is homogeneous, has a dense morphology and is totally polycrystalline. After being coated with the Y 2 O 3 film, the transmission of the sapphire substrate is improved and the emissivity is decreased with increasing film thickness, especially at high temperatures. Simulation results show that apparent emissivity of a sapphire substrate at high temperatures can be reduced effectively by the Y 2 O 3 film when the ratio of the thickness of Y 2 O 3 film and sapphire substrate is larger than 0.01. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly crystalline In 2 O 3 films are grown by pulsed reactive magnetron sputtering. • Substrate heating further improves the film crystallinity and conductivity. • 400 °C is the limit for benefiting to obtain the optimum crystallinity of In 2 O 3 films. • The films deposited at 400 °C yield the lowest resistivity of 1.28 × 10-4 Ω⋅cm. • An average transmittance of greater than 80% are also obtained at 400 °C. A transparent conductive oxide (TCO) should have a combination of high electrical conductivity and optical transmission property to fulfill the challenging demands of industrial applications. So far, doped TCOs have been mostly considered to fulfill the technological challenges. In this study, we demonstrate that indium oxide (In 2 O 3) thin films without intentional doping can be deposited with high crystallinity under specific film growth conditions leading to thin films with high mobility, high electrical conductivity, and high transmittance. In 2 O 3 thin films have been deposited by reactive pulsed direct current magnetron sputtering (pulsed DCMS) from an indium target on substrates in a temperature range from room temperature (RT) to 600 °C. Detailed investigations on In 2 O 3 thin films are performed and the film properties such as crystallinity, microstructure, chemical bonding states, electrical and optical properties are revealed. Enhanced plasma density and ionization degree provided by the employed reactive pulsed DCMS and the intentional substrate heating during the thin film deposition give possibility to deposit highly crystalline thin films which are preferentially oriented in (2 2 2) direction. The substrate heating enhances the crystallinity of the grown films up to a certain optimum temperature: 400 °C. When the substrate temperature is above 400 °C, the carrier concentration and mobility decrease due to the grain refinement effect caused by growth competition of grains in different orientations. The films grown at 400 °C indicate the presence of high oxygen vacancy concentrations, which can directly be associated with a high charge carrier concentration despite the lack of intentional doping. The undoped In 2 O 3 films in this study grown at 400 °C show highly promising and competitive electrical properties such as low resistivity of 1.28 × 10-4 Ω⋅cm and the high carrier mobility of 69 cm2/Vs. The average transmittance of the In 2 O 3 films with the highest conductivity is found to be greater than 80% in the visible to the near-infrared spectral region owing to an enhancement in the carrier mobility and an optical bandgap in the range from 3.61 eV to 3.77 eV. [ABSTRACT FROM AUTHOR]

In this study, the reaction mode of high-power pulsed reactive magnetron sputtering and the crystal structure and infrared transparent conductive properties of SnOx thin films prepared at 600 °C were investigated. The effects of sputtering at different oxygen partial pressures from 10 to 24 sccm were examined. For SnOx films deposited at oxygen partial pressures of 10–14 sccm, the reaction mode was dominated by the metallic mode, and the polar unsaturated (101) plane was the preferred orientation of the film crystals. For SnOx films deposited at oxygen partial pressures of 16–18 sccm, the reaction mode was dominated by the transition mode, showing a preferred (110) plane orientation. In the deposition process, at oxygen partial pressure >18 sccm, the reaction proceeded in poisoning mode. As the oxygen partial pressure was increased, the carrier concentration decreased to 1.140 × 1015 cm−3, mobility increased to 14.93 cm2/Vs, and IR transmittance at 4 μm increased. Furthermore, excess O 2 resulted in deteriorated electrical properties of the prepared SnOx films, with a maximum resistivity of 502.9 Ω·cm. [Display omitted] • SnO x films prepared using high-power pulsed reactive magnetron sputtering at 600 °C • Crystal structures and infrared transparent conductive properties examined • Effects of sputtering at different oxygen partial pressures examined • At 16–18 sccm (O 2 partial pressure), reaction mode dominated by the transition mode • SnO x films with deteriorated electrical properties were formed due to excess O 2 [ABSTRACT FROM AUTHOR]

Vanadium pentoxide (V 2 O 5) films were deposited on sapphire substrates by radio frequency (R.F.) magnetron sputtering at 450 °C and annealed in various ambient atmospheres. The influence of ambient atmospheres on the structure, optical properties, and morphology of the thin films after annealing were characterized, and the transition behaviors in the annealing process were investigated by DSC, temperature-dependent Raman and FTIR. The results demonstrated that V 2 O 5 films underwent four different transition behaviors during post-deposition annealing due to the different oxygen proportion of ambient. Different products (VO 2 (B), VO 2 (R)) in the transition process were the main reason for the evolution of optical properties. No transition behaviors occurred because of the oxygen-rich ambient when annealed in air, and no significant change in infrared transmittance was observed. When annealed in 0.1% O 2 /Ar, the film was converted to VO 2 (B) with the decrease of infrared transmittance. In the case of 0.01% O 2 /Ar, metastable VO 2 (B) and VO 2 (R) were observed as intermediate crystalline phases before V 2 O 5 finally transformed to VO 2 (M), and the changes in the three stages of two drops and one rise were shown in infrared transmittance. While annealed in pure argon ambient, V 2 O 5 was turned into VO 2 (R) and VO 2 (M) without VO 2 (B) phase production, accompanied by a single change of infrared transmittance reduction and recovery. This provides a more detailed vanadium oxide thermal transition process and shows data reference for the preparation technology and application of vanadium oxide materials. • V 2 O 5 films were deposited on sapphire substrates by radio frequency (R.F.) magnetron sputtering; • Effect of the different oxygen proportion during annealing on thermal transition behaviors was investigated in detail by temperature-dependent Raman and FTIR; • The annealed V 2 O 5 films were transformed into V 2 O 5 , VO 2 (B), and VO 2 (M) by different thermal transition behaviors; • VO 2 (M) films with excellent thermochromic properties can be obtained by controlling the annealing atmosphere and temperature. [ABSTRACT FROM AUTHOR]

• Both reversible and irreversible transition were found in VO x films with different temperature. • Transmittance of VO x film were found undergoes twice reductions with temperature. • Mid infrared transmittance with ~64% modulation with temperature after the decomposition. • Temperature dependent Raman reveal the phase transition and decomposition process with temperature. In this study, mid infrared optical modulation property of VO x films with temperature was researched. VO x film which contain both VO 2 and V 2 O 5 was deposited on Al 2 O 3 substrate by radio frequency magnetron sputtering. The mid infrared transmittance undergoes two reductions when increasing the temperature to 590 °C, the first reversible reduction around 68 °C as the phase transition of VO 2 and the second irreversible gradually reduction starting around 350 °C because the oxidation state changed from V 2 O 5 to VO 2. The transmittance increased from 5.49% to 70.29% when cooling the temperature around 54℃. The film has the reversible 64% optical modulation around 60 °C during the second thermal cycling and keep stable even increased the temperature higher than 550 °C. The difference caused by high temperature thermal cycling in surface morphology structures, and chemical composition, were characterized by AFM, XRD, Raman, and XPS. The process of phase transition and the oxidation state changed during the thermal cycles were monitored with temperature dependent Raman spectra. This study provides new information about the transition between different structures and oxidation states of VO x film and a good candidate for infrared thermochromic window. [ABSTRACT FROM AUTHOR]

• A self-powered vertical heterojunction photodetector based on n-SnOx/p-diamond was fabricated by RF sputtering. • The device has a peak response at 350 nm and responds to light wavelength in the 250–500 nm range at zero bias. • Analysis of the detection mechanism of the n-SnOx/p-diamond heterojunction photodetector. High-performance self-powered UV-blue photodetector was fabricated based on n-SnO x /p-diamond heterojunction. The SnO x film was deposited on the high temperature and high pressure synthetic boron doped diamond wafer by RF magnetron sputtering. This heterojunction device exhibits a good rectification behavior with a rectification ratio of 3.15 × 104 at ±3 V. At zero bias, the device responds in the wavelength ranging from 250 nm to 500 nm with a peak response at 350 nm. The photoresponse rise time and decay time of the device are both less than 2 s under UV-blue illumination with different wavelengths. These results demonstrate that the n-SnO x /p-diamond heterojunction device has potential applications in the field of UV-blue detection. [ABSTRACT FROM AUTHOR]