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• 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]

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]

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]

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]

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]