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In order to evaluate the effect of cutoff criteria on spectral temperature measurement, partition functions are calculated for argon plasma at 3000–30 000 K using three different cutoff criteria (semi-empirical method, NIST data, and Griem's theory). The effects of cutoff criteria on particle number density and plasma temperature measurements were discussed. The results indicate that as the plasma temperature increases, the degree of particle ionization increases and the cutoff effect weakens. The cutoff criteria have little impact on the calculation of the number density of the main components of the plasma but have a significant impact on the calculation of the number density of non-major components. The cutoff criterion using the NIST data can be reliably used for the temperature measurement, especially when the standard temperature method is used. Nevertheless, Griem's theory should be considered for accurate calculation of radiation intensity. [ABSTRACT FROM AUTHOR]

We present a method for measuring thermal expansion under tunable uniaxial stresses and show measurements of the thermal expansion of Mn3Sn, a room temperature antiferromagnet that exhibits a spontaneous Hall effect, under uniaxial stresses of up to 1.51 GPa compression. The measurement of thermal expansion provides thermodynamic data about the nature of phase transitions, and uniaxial stress provides a powerful tuning method that does not introduce disorder. Mn3Sn exhibits an anomaly in its thermal expansion near ∼270 K, associated with a first-order change in its magnetic structure. We show that this transition temperature is suppressed by 54.6 K by 1.51 GPa compression along [0001]. We find the associated entropy change at the transition to be ∼ 0.1 J mol−1 K−1 and to vary only weakly with applied stress. [ABSTRACT FROM AUTHOR]

To improve the dielectric properties of sputter-deposited hafnium oxide (HfO2) films, the supercritical CO2 (SCCO2) fluid technology is introduced as a low temperature treatment. The ultrathin HfO2 films were deposited on p-type (100) silicon wafer by dc sputtering at room temperature and subsequently treated with SCCO2 fluids at 150 °C to diminish the traps in the HfO2 films. After SCCO2 treatment, the interfacial parasitic oxide between the Si substrate and HfO2 layer is only about 5 Å, and the oxygen content of the HfO2 films apparently increased. From current-voltage (I-V) and capacitance-voltage (C-V) measurements, the leakage current density of the SCCO2-treated HfO2 films is repressed from 10-2 to 10-7 A/cm2 at electric field=3 MV/cm due to the reduction of traps in the HfO2 films. The equivalent oxide thickness also obviously decreased. Besides, the efficiency of terminating traps is relative to the pressure of the SCCO2 fluids. [ABSTRACT FROM AUTHOR]

Lateral heterojunctions based on two dimensional (2D) transition metal dichalcogenides (TMDCs) potentially realize monolayer devices exploiting 2D electronic structures and the functions introduced by the presence of 1D heterointerfaces. Electronic structures of a lateral MoSe2-WSe2 junction have been unveiled using scanning tunneling microscopy and spectroscopy. A smooth and narrow depletion region exists despite a defect-rich heterointerface deviating from the preferred zigzag orientations of the TMDC lattice. From the characteristics of the depletion region, a high carrier concentration and high internal electric fields are inferred, offering to benefit designs of lateral TMDC devices. [ABSTRACT FROM AUTHOR]

Thin film transistors (TFTs) with amorphous silicon films crystallized via continuous-wave green laser at a wavelength of 532 nm exhibit very different electrical characteristics in various crystallization regions, corresponding to the Gaussian energy density distribution of the laser beam. In the center region subjected to the highest energy density, the full melting scheme led to the best crystallinity of the polycrystalline silicon film, resulting in the highest field-effect mobility of 500 cm2 V-1 s-1. In contrast, the edge region that resulted in solid phase crystallization exhibited the worst mobility of 48 cm2 V-1 s-1 for the polycrystalline silicon TFTs. [ABSTRACT FROM AUTHOR]

In this paper, the surface morphology transformation of the sprayed carbon nanotube (CNT) thin film irradiated with the excimer laser has been systematically investigated. Under the excimer-laser irradiation, two phenomena, including the annealing and ablation effects, were found to be dependent on the incident laser energy and overlapping ratios. Moreover, the extremely high protrusions would be produced in the interface between the annealing and ablation regions. The mechanism of the CNT thin film under the excimer laser irradiation was, therefore, proposed to derive the surface morphology modifications and the further reinforced crystallinity with proper laser energy densities and overlapping ratios. [ABSTRACT FROM AUTHOR]

An excimer-laser-crystallized polycrystalline-silicon silicon-oxide-nitride-oxide-silicon thin-film transistor with recessed-channel structure has been designed to achieve only one grain boundary with a protrusion perpendicular to the channel for investigating the grain boundary location effects on the memory characteristics. After programming, the devices demonstrated better memory characteristics as the grain boundary was allocated near the source junction. In contrast, the memory characteristics were degraded when the grain boundary was located near the drain junction. The phenomenon was explained by the 2-D device simulation and the energy band diagrams. [ABSTRACT FROM AUTHOR]

Performance of substrate-configured hydrogenated amorphous silicon solar cells based on ZnO nanorod arrays prepared by hydrothermal method has been investigated. The light harvest ability of three-dimensional nanorods solar cells is a compromise between the absorber layer thickness and the nanorods geometry. By optimizing the intrinsic a-Si:H absorber layer thickness from 75 to 250 nm and varying the length of the nanorods from 600 to 1800 nm, the highest energy conversion efficiency of 6.07% is obtained for the nanorods solar cell having thin absorber layer thickness of 200 nm with the rod length of 600 nm. This represents up to 28% enhanced efficiency compared to the conventional flat reference cell with similar absorber layer thickness. [ABSTRACT FROM AUTHOR]

This paper investigates the improvement of resistive switching trends after post-forming negative bias stress treatment of a Pt/Yb2O3/TiN device that has undergone positive bias forming process for activation. After the treatment, characteristics of the conductive filament, such as the temperature dependence of resistivity and transition mechanism, undergo changes. Furthermore, this treatment causes the conductive filament to transform from being primarily composed of vacancies to being metallic Yb dominant, which not only reduces operation voltages such as Vset and Vreset but also improves the on/off ratio. In reliability tests, the device has stable retention. [ABSTRACT FROM AUTHOR]

A low-temperature method, supercritical CO2 fluid (SCF) technology, is proposed to improve the dielectric properties of ultrathin hafnium oxide (HfO2) film at 150 °C without significant formation of parasitic oxide at the interface between HfO2 and Si substrate. In this research, the HfO2 films were deposited by dc sputter at room temperature and post-treated by SCF which is mixed with 5 vol % propyl alcohol and 5 vol % H2O. From high-resolution transmission electron microscopy image, the interfacial oxide of SCF-treated HfO2 film is only 5 Å thick. Additionally, the enhancements in the qualities of sputter-deposited HfO2 film after SCF process are exhibited by x-ray photoelectron spectroscopy and capacitance-voltage (C-V) measurement. [ABSTRACT FROM AUTHOR]

The authors report a pixel structure for active-matrix organic light-emitting diode (OLED) displays that has a hydrogenated amorphous silicon solar cell inserted between the driving polycrystalline Si thin-film transistor and the pixel OLED. Such an active-matrix OLED pixel structure not only exhibits a reduced reflection (and thus improved contrast) compared to conventional OLEDs but also is capable of recycling both incident photon energies and internally generated OLED radiation. Such a feature of energy recycling may be of use for portable/mobile electronics, which are particularly power aware. [ABSTRACT FROM AUTHOR]

Low-temperature supercritical fluid (SCF) technology is employed to improve the dielectric characteristics of metal oxide film deposited at low temperature. In this investigation, hafnium oxide (HfO2) film was sputter deposited at room temperature and post-treated with SCF at 150 °C, replacing typical high-temperature annealing process. From Fourier transformation infrared and thermal desorption spectroscopy measurement, the absorption peaks of Hf–O–Hf bonding and the oxygen content in HfO2 film have, respectively, shown apparent raise. The leakage current density of the low-temperature deposited HfO2 film is reduced significantly, and the conduction mechanism is modified from trap-assisted quantum tunneling to thermionic emission process, since SCF treatment effectively reduces the number of traps in HfO2 film. [ABSTRACT FROM AUTHOR]

A plasmonic-structure incorporated double layer of Au nanoparticles embedded in the transparent conducting oxide at the back-reflector of the hydrogenated amorphous silicon (a-Si:H) solar cells is demonstrated. These devices exhibit an increase of energy conversion efficiency of 18.4% and short-circuit current density of 9.8% while improving fill-factor and without sacrificing open-circuit voltage. The increase in photocurrent is correlated with the enhanced optical absorption in the cell, with improved optical-path-length by a factor of 7 at the wavelength of 800 nm, due to enhanced diffuse scattering of light through resonant plasmon excitations within Au nanoparticles. In addition to enhanced scattering, applying high-work-function Au nanoparticles can improve the work function match at TCO/a-Si:H interface. [ABSTRACT FROM AUTHOR]

This report compares Mo-doped and undoped SiO2 thin films of a similar thickness as well as MoOx. The Mo-doped SiO2 film exhibited switching behavior after the forming process, unlike the undoped SiO2 film. Through material analyses, a self-assembled layer is observed in the Mo-doped SiO2 film. Due to the formation of this layer, the thickness required to be broken down is effectively reduced. Subsequently, the occurrence of the switching behavior in the thinner SiO2 film further confirmed the supposition. A comparison of the two switching behaviors shows that SiO2 dominates the switching characteristic of the Mo-doped SiO2. [ABSTRACT FROM AUTHOR]

The recovery mechanism of the light-induced instability of amorphous InGaZnO thin-film transistors was examined. Following light illumination, the bare devices displayed more dark recovery of the threshold voltage (Vth) shifts than the ones encapsulated in nitrogen ambient. This was attributed to the adsorption of more oxygen (O2) in the back channel of the bare devices. Further, much more recovery was also observed for the bare devices than the nitrogen-encapsulated ones under positive gate bias. This implied the recovery effect under gate bias could be further enhanced because the induced electrons could greatly increase the adsorption of more O2 for the bare devices. [ABSTRACT FROM AUTHOR]

CdSexS1-x quantum dots (QDs) were synthesized by a simple one-injection non-coordinate solvent method. The composition distribution of Se and S and the internal structures of the CdSexS1-x QDs can be tuned by the Se/S molar ratio. To investigate the internal structure of CdSexS1-x QD, x-ray absorption spectroscopy was used to examine the distribution of Se and S inside CdSexS1-x QDs. [ABSTRACT FROM AUTHOR]