Encapsulation of organic light-emitting diodes (OLEDs) is the only way to prevent degradation due to the penetration of moisture and oxygen. However, the upper encapsulation layer, located in the ...path through which light from the OLED passes, adversely affects light transmission. In this study, we calculated the optical transmittance by using admittance trajectory simulation and compared the data with actual Al
2
O
3
/TiO
2
multilayer film processed by atomic layer deposition (ALD). By applying the simulated data on to actual encapsulation layer, we can observe the optical transmittance increase of up to 8% compared to the film of Al
2
O
3
/TiO
2
/Al
2
O
3
structure. Over 90% of optical transmittance was achieved for all the visible wavelength ranges while maintaining water vapor transmission rate (WVTR) of the processed multilayer thin film as low as of 5 × 10
−5
g/m
2
/day, which was measured using MOCON Aquatran 2.
In this study, inkjet-printed zinc tin oxide:Cl (ZTO:Cl) thin films were analyzed using x-ray diffraction, x-ray photoelectron spectroscopy (XPS) and all the films were annealed at temperatures ...ranging from 100°C to 600°C. XPS analysis showed that the formation of metal-oxide bonds in the films was complete with annealing temperatures at or above 500°C. Furthermore, inkjet-printed thin film transistors (TFTs) were examined using scanning electron microscopy and current–voltage characteristic measurements. The ZTO:Cl TFTs performed best when annealed at 500°C. The average carrier mobility and the on/off ratio were found to be 2.71 cm
2
/V s and 1.82 × 10
7
, respectively.
The effect of SiO₂ buffer layers with various atomic densities on the interface dipole of high-k/SiO2 is confirmed. An ultrathin SiO₂ layer is formed on Si using the plasma-enhanced chemical vapor ...deposition (PECVD), H2O2 oxidation and nitric acid oxidation (NAOS). The atomic density ratio between the SiO2 layer with various methods and the high-k is calculated respectively. As the oxygen density of the SiO2 increased, the amount of the dipole and the flatband voltage (VFB) shift decreased. Furthermore, leakage current density of the H2O2 (0.9 × 10−2 A/cm2) due to the formation of low-density SiO2, decreases by approximately six orders of magnitude when SiO2 buffer layer is inserted using the NAOS (5.13 × 10-8 A/cm2). Consequently, it is demonstrated that the dipoles that affects the VFB shift is formed by the diffusion of oxygen ions between the high-k and SiO2 interface, which has a significant effect of the MOS capacitor.
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•TiN/Al2O3/SiO2/Si capacitor was structured through various SiO2 oxidation methods.•In order to remove the thickness effect, the thickness of the SiO2 buffer layer is fixed to ∼2 nm.•The dipole is formed by the diffusion of oxygen ions between the high-k and SiO2 interface.•The SiO2 buffer layers with various oxygen density affects flatband voltage to shift.
Transparent and conducting gallium-doped ZnO electrodes were fabricated by means of atomic layer deposition. The electrode showed the lowest resistivity of 7.19×10−4Ωcm at a 5% cyclic layer ...deposition ratio of Trimethyl-gallium and Diethyl-zinc chemicals. The electrodes showed minimum resistivity when deposited at a temperature of 250°C. The electrode also showed optical transmittance of about 82%–89% with film thicknesses between 100nm and 300nm. An organic solar cell made with a 300-nm-thick gallium-doped ZnO electrode exhibited 2.5% power conversion efficiency, and an efficiency equivalent to that of cells made with conventional indium tin oxide electrodes.
•Ga-doped ZnO thin films were successfully grown by atomic layer deposition•The grown thin film has low resistivity compatible to conventional ITO electrodes•The Ga-doped ZnO films were successfully integrated into organic solar cells•The power conversion efficiency was equivalent to the cells with ITO electrodes
A phase-change material of Sb/sub 65/Se/sub 35/ was newly proposed for the nonvolatile memory applications. The fabricated phase-change memory device using Sb/sub 65/Se/sub 35/ showed a good ...electrical threshold switching characteristic in the dc current-voltage (I-V) measurement. The programming time for set operation of the memory device decreased from 1 μs to 250 ns when Sb/sub 65/Se/sub 35/ was introduced in place of the conventionally employed Ge 2 Sb 2 Te 5 (GST). The reset current of Sb/sub 65/Se/sub 35/ device also dramatically reduced from 15 mA to 1.6 mA, compared with that of GST device. These results are attributed to the low melting temperature and high crystallization speed of Sb/sub 65/Se/sub 35/ and will contribute to lower power and higher speed operations of a phase-change nonvolatile memory.
Inverted-structure organic solar cells (OSCs) were fabricated using atomic-layer-deposition (ALD) processed Ga-doped TiO
2
as hole blocking layer (HBL). Measured photovoltaic efficiencies were ...greatly related to the crystallinity of the TiO
2
films. However, the efficiencies of the OSCs and the crystallinity of the HBL did not show a linear relationship. The HBL was fully crystallized at a deposition temperature of 200 °C or above, and the power conversion efficiency was measured to be 2.7% with for the HBL processed at 200 °C, but the efficiency decreased to 2.4% for the HBL processed at 250 °C. On the other hand, the surface roughness of the crystallized films was found be increased to two fold in the studied temperature range. Once the HBL had been fully crystallized, the major factor that determined the overall performance of OSCs was the surface roughness of the HBL.
A large GaN-Schottky barrier diode (SBD) with a recessed dual anode metal is proposed to achieve improved the forward characteristics without a degradation of the reverse performances. Using ...optimized dry etch condition for a large device, the electrical characteristics of the device are demonstrated when applying the recessed dual anode metal and changing the recess depths. The device size and channel width are 4 mm 2 and 63 mm, respectively. The 16-nm recessed dual anode metal SBD has a turn-ON voltage of 0.34 V, a breakdown voltage of 802 V, and a reverse leakage current of 1.82 μA/mm at -15 V. The packaged SBD exhibits a forward current of 6.2 A at 2 V and a reverse recovery charge of 11.54 nC.
Artificial muscles are indispensable components for next-generation robotics capable of mimicking sophisticated movements of living systems. However, an optimal combination of actuation parameters, ...including strain, stress, energy density and high mechanical strength, is required for their practical applications. Here we report mammalian-skeletal-muscle-inspired single fibres and bundles with large and strong contractive actuation. The use of exfoliated graphene fillers within a uniaxial liquid crystalline matrix enables photothermal actuation with large work capacity and rapid response. Moreover, the reversible percolation of graphene fillers induced by the thermodynamic conformational transition of mesoscale structures can be in situ monitored by electrical switching. Such a dynamic percolation behaviour effectively strengthens the mechanical properties of the actuator fibres, particularly in the contracted actuation state, enabling mammalian-muscle-like reliable reversible actuation. Taking advantage of a mechanically compliant fibre structure, smart actuators are readily integrated into strong bundles as well as high-power soft robotics with light-driven remote control.
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