Optically transparent materials with p-type electrical conductivity can facilitate the development of transparent electronics and improve the efficiency of photovoltaic solar cells. Sulfide materials represent an interesting alternative to oxides for these applications due to better hole transport properties. Here, transparent and conductive Ba–Cu–S thin films are prepared by combinatorial cosputtering and characterized for their composition, structure, and optoelectronic properties. The conductivity and transparency of these films are found to be strongly dependent on their chemical composition and the substrate temperature during growth. The conductivity of BaCu2S2 and BaCu4S3 can reach 53 S/cm (at 250 °C) and 74 S/cm (at 200 °C), respectively, which is higher than their solution processed/bulk counterparts. The 90% reflectance corrected transmittance is achieved in the wavelength range 600–1000 nm for BaCu2S2 and 650–1000 nm for BaCu4S3 (at 250 °C). These electrical and optical properties are comparable with other recently presented transparent p-type conductors, while the 200–350 °C processing temperature is low enough to be used in semiconductor devices with limited thermal budgets. Attempts have been made to synthesize the related Sr–Cu–S materials, following the theoretical suggestion of their potential as transparent p-type conductors, but these attempts resulted only in phase-separated SrS and CuxS phases. Alloying BaCu2S2 with Sr on the Ba site on the other hand increases the conductivity to >100 S/cm while only slightly compromising the transparency of the material. To explain the difference between the Ba and the Sr containing copper sulfides, the lower bounds on the SrCu2S2 and SrCu4S3 formation enthalpies are estimated. While the doping of the Ba–Cu–S materials presented here is too large for application in transparent electronics, it is promising for potential use as p-type contact layers in thin film solar cells.

•a-IZO-TFTs with different channel layer thickness were fabricated.•The initial characteristics and aging effect on the thickness were investigated.•The PBS and NBS stabilities of initial and aged a-IZO-TFTs were compared.•Thin channel layer a-IZO-TFTs exhibit good anti-aging effect and bias stability.Amorphous indium zinc oxide (a-IZO) thin film transistors (TFTs) with different channel layer thickness were fabricated on silicon wafers by radio frequency magnetron sputtering method at room temperature. The influence of channel layer thickness on initial electrical characteristics and aging effect of a-IZO-TFTs were investigated. At the same time, the positive / negative bias stress stability of initial and 60-days-aged a-IZO-TFTs were compared. All results indicate that thin channel layer a-IZO-TFTs exhibit good anti-aging effect and bias stability.

The dependence of the electrical properties of amorphous lanthanum–zinc–tin–oxides (a-LZTOs)-based top-gate thin-film transistors (TFTs) on active layer thicknesses (dT) is investigated. It is found that the on-to-off current ratio (Ion/off) of TFT improved with the thickness of LZTO active layer decreased from 84 nm to 32 nm, whereas the saturation mobility and the subthreshold swing of device degraded. The improvement in Ion/off is attributed to the decrease in off-current of TFT due to an increase in resistance of the very thin LZTO film. Moreover, the deterioration in properties of device with the thin active layer is associated with the trap states incorporated in TFT and interface scattering effect.Highlights► The device properties of a-LZTO TFTs with various LZTO thicknesses were examined. ► As LZTO thickness decreased, Ion/off improved, whereas μsat and SS degraded. ► Mechanism about the dependence of TFTs’ property on LZTO thickness was studied.

Transparent p-type conducting K-doped NiO thin films were prepared by pulsed plasma deposition. The structural, electrical and optical properties of the films were investigated using X-ray diffraction, atomic force microscope, X-ray photoelectron spectroscopy, Hall measurement, and ultraviolet–visible spectroscopy, respectively. The dependency of film properties on K doping content and substrate temperature was studied. The film with K doping content of 25 at.% deposited at room temperature exhibits the highest conductivity of 4.25 S cm− 1 and an average transmittance of nearly 60% in visible light region.Highlights► P-type K-doped NiO films were deposited by pulsed plasma deposition. ► The resistivity of the films is lowered with proper doping content. ► The film crystallinity is improved with the increase of substrate temperature. ► The film deposited at room temperature exhibits the conductivity of 4.25 S cm− 1.

Transparent p-type conductive Ni0.9Cu0.1O thin films were prepared by pulsed plasma deposition (PPD) method. The effects of substrate temperature and oxygen pressure on the structural, electrical and optical properties of the films were investigated respectively. The film deposited at room temperature exhibits the highest conductivity of 5.17 S cm−1, with an average transmittance of 60% in the visible region. A transparent p-Ni0.9Cu0.1O/n-In2O3:W (IWO) hetero-junction diode was fabricated exhibiting rectifying current–voltage characteristics.

Amorphous indium zinc oxide (IZO) thin films were prepared on glass substrates by dc magnetron sputtering at room temperature. The resistivity of IZO films could be controlled between 3.8 × 10−3 and 2.5 × 106 Ω cm by varying the oxygen partial pressure during deposition, while keep the average transmittance over 83%. With IZO films as channel layers, whose surface root-mean-square roughness was less than 1 nm, thin film transistors were fabricated at room temperature, showing enhanced mode operation with good saturation characteristics, mobility of 5.2 cm2 V−1 s−1, threshold voltage of 0.94 V and on/off ratio of ∼104.

Transparent conductive tungsten-doped tin oxide (SnO2:W) thin films were synthesized on quartz glass substrates by sol–gel dip-coating method. It was found that the films were highly transparent and the average optical transmission was about 90% in the visible and near infrared region from 400 to 2,500 nm. The optical band gap is about 4.1 eV. The lowest resistivity of 5.8 × 10−3 ohm cm was obtained, with the carrier mobility of 14.2 cm2 V−1 s−1 and carrier concentration of 7.6 × 1019 cm−3 in 3 at.% W-doping films annealed at 850 °C in air. The structural properties, surface morphology and chemical states for the films were investigated.

Tungsten-doped tin oxide (SnO2:W) transparent conductive films were prepared on quartz substrates by pulsed plasma deposition method with a post-annealing. The structure, chemical states, electrical and optical properties of the films have been investigated with tungsten-doping content and annealing temperature. The lowest resistivity of 6.67 × 10− 4 Ω cm was obtained, with carrier mobility of 65 cm2 V− 1 s− 1 and carrier concentration of 1.44 × 1020 cm− 3 in 3 wt.% tungsten-doping films annealed at 800 °C in air. The average optical transmittance achieves 86% in the visible region, and approximately 85% in near-infrared region, with the optical band gap ranging from 4.05 eV to 4.22 eV.

Amorphous tungsten-doped In2O3 (IWO) films were deposited from a metallic target by dc magnetron sputtering at room temperature. Both oxygen partial pressure and sputtering power have significant effects on the electrical and optical properties of the films. The as-deposited IWO films with the optimum resistivity of 5.8 × 10−4 Ω·cm and the average optical transmittance of 92.3% from 400 to 700 nm were obtained at a W content of 1 wt%. The average transmittance in the near infrared region (700–2500 nm) is 84.6–92.8% for amorphous IWO prepared under varied oxygen partial pressure. The mobility of the IWO films reaches its highest value of 30.3 cm2 V−1 s−1 with the carrier concentration of 1.6 × 1020 cm−3, confirming their potential application as transparent conductive oxide films in various flexible devices.

Tungsten-doped indium oxide (IWO) thin films were prepared by reactive magnetron sputtering method. The dependence of optical and electrical properties on the thickness of IWO films was investigated. X-ray diffraction analysis indicates that the preferential orientation of IWO films varies from (111) to (100) with the increase of the thickness. The carrier mobility and resistivity are sensitive to the film thickness at a range of 50–150 nm. A sample with electrical resistivity of 2.7 × 10− 4 Ω cm, carrier mobility of 49 cm2 V− 1 s− 1, and transmission at the visible region of more than 80% was obtained.

Ag–TCNQ organometallic complex with single phase and uniform grains in nanometer scale were prepared by vacuum evaporation and post-heat treatment. The grain size of the films was decreased by introducing the post-heat treatment process to about 50 nm. By applying a ramp voltage onto the film through STM probe tip in air at room temperature, the film will transfer from high impedence to low impedence at about 2.0 V. A writing dot of about 70 nm in diameter, corresponding to the low impedence state, was obtained after applying a pulse voltage of 5.0 V in amplitude and 5.0 ms in duration.