Search

Anion doping is an efficient method for modifying the electrical property of the p‐type semiconductor CuI. However, adjustment of the hole density is still challenging. Using sputtering and spin coating techniques, well‐controlled S‐doping of CuI thin films has been realized. The spin‐coated samples present a single (111) out‐of‐plane orientation and very high crystallinity, which is comparable with previously reported epitaxial CuI thin films. The sputtered thin films have advantages in surface morphology and conductivity. Substituting S for I can achieve efficient acceptor doping of CuI for both the physical and chemical growth methods. The highest conductivity of CuI appears at 2.0 at% of S doping, and the doping efficiency is influenced by the self‐compensation effect. [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 As lanthanum oxide (La 2 O 3) has a large bandgap, it exhibits excellent optical properties. In this work, La 2 O 3 thin films are prepared by the sol-gel method from a lanthanum chloride (LaCl 3) precursor, on quartz and sapphire (0001) substrates. The effect of the annealing temperature (400–800 °C) on the optical properties of the La 2 O 3 films is investigated. The structure and optical properties are analyzed by X-ray diffraction, atomic force microscopy, scanning electronic microscopy, X-ray photoemission spectroscopy, Raman spectroscopy, ultraviolet (UV)–visible spectroscopy, Fourier transform infrared spectroscopy, and infrared variable angle spectroscopic ellipsometry. Results indicate that with an annealing temperature of ~600 °C, the roughness and optical properties of La 2 O 3 films can be significantly improved. Highlights • La 2 O 3 thin films are prepared by sol-gel method on quartz and sapphire substrates. • Effect of annealing temperature on their optical properties is investigated. • Results indicate that the best annealing temperature is around 600 °C. • The roughness and optical properties of films are significantly improved. [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]

Abstract High-quality, transparent, conducting, p-type γ-CuI thin films are prepared via an innovative layer-by-layer procedure based on the traditional simple iodination of Cu films (referred to as the LBL-I method) at room temperature (RT). The structure, morphology, and optoelectronic properties of the γ-CuI are investigated as functions of the per layer thickness. The final thicknesses of LBL-I γ-CuI films are consistent with that in the film prepared by the traditional one-step method (TOS). X-ray diffraction analysis reveals that all the films are polycrystalline with the most dominant (111) direction of the zinc blende structure, indicating the facile and successful fabrication of γ-CuI. Compared with the TOS film, the LBL-I films display enhanced transmittance and mobility. The higher transmittance of >80% in the visible region of LBL-I films was attained due to the smaller root-mean-square roughness values of 23–28 nm. The 50 nm/ l LBL-I CuI films have mobility values of 6.9–9.4 cm2 V−1 s−1, and lower resistivity of 0.039–0.05 Ω cm, which assist studies on applications of γ-CuI thin films in transparent electronics. Highlights • High-quality electrooptical properties p-type γ-CuI thin films are prepared. • Innovative layer-by-layer approach based on Cu films iodination (LBL-I) is used. • LBL-I films show better transmittance and mobility than films prepared in one step. [ABSTRACT FROM AUTHOR]

Abstract In p-type γ -CuI thin films synthesized by the iodination of Cu layers with iodine vapor, a frosted-glass-like appearance with a rough surface is usually obtained, which makes it difficult to apply the γ -CuI films to transparent electronics. This paper proposes an innovative method for the preparation of highly transparent p-type γ -CuI films. A chemical reaction between Cu thin films and iodine vapor, combined with the layer-by-layer process at a temperature between room temperature and 120 °C are found to result in highly transparent polycrystalline γ -CuI films. The root-mean-square roughness values of the γ -CuI films prepared by this method are 8.5–21.2 nm, which are smaller than those for the γ - CuI films synthesized by the conventional method. The microstructure and optoelectronic properties of the γ-CuI thin films are sensitive to the temperature of iodine vapor. A high transmittance (80%) of the film obtained at an iodine vapor temperature of 80 °C has a low resistivity of 5 × 10−2 Ω cm and high mobility of 8.7 cm2/Vs. Moreover, a boosted figure of merit is realized due to the simultaneously low resistivity and high transparency: its value jumps from ∼488 to ∼1630 MΩ−1. Graphical abstract Unlabelled Image Highlights • A traditional iodination reaction method combined with the layer-by-layer process. • Simultaneously high transmittance and low resistivity. • A boosted figure of merit is realized. [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]

The hydrated magnesium-carbon films fabricated in this study are the novel-innovative non-oxide-type transparent electronic material. The films, which have a structure similar to that of magnesium hydroxide, were produced by making Mg x -C y films deposited by magnetron co-sputtering react with water vapor. As the extrinsic defect of hydration magnesium-carbon films, C atoms provided redundant electrons, resulting in a conductivity of approximately 3.31 × 10 −2  Ω·cm. 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 72% for a plasma wavelength of approximately 10 μm. By varying the atomic C content of the films, a visible-region transmittance greater than 80% could be realized. The optical bandgap of the films was approximately 4.04–6.87 eV and was blue-shifted because of the Moss-Burstein effect. [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]

The performance of atomic layer deposition films is mainly limited by precursor residues, low crystallinity and densities due to low deposition temperatures. Here, we used atomic layer deposition to deposit tin oxide thin films at a relatively low temperature of 250 °C. At this temperature, the change in the valence of Sn due to precursor residue is eliminated by layer-by-layer Ar plasma treatment, and the crystallinity of the films is improved. The effects of Ar plasma treatment power and Ar treatment time on the structural and optoelectronic properties were investigated. It was found that Ar plasma treatment time more significantly affects the surface morphology and the optical and electrical properties of the film. The film is transparent to both visible and near-infrared light over a wide range of wavelengths from 400 nm to at least 5000 nm. The film resistivity can be as low as 1.117 × 10−3 Ω·cm. The film has a relatively low level of residual stress due to the fact that there is no need to improve the crystallinity of the film by conventional high temperature annealing. On the basis of the high transparency and high conductivity of the SnOx films with layer by layer Ar plasma treatment in situ, the films can be applied as electromagnetic shielding windows for photodetectors. Unlabelled Image • The films exhibit excellent crystallinity and conductivity without the need for a high-temperature annealing step. • Ar plasma treatment significantly reduced the proportion of reduced Sn4+. • The plasma treatment time has a more pronounced effect on the SnOx crystallinity than the treatment power. • Designed and prepared an infrared transparent conductive film with excellent electrical properties and optical transmission [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]