Analysis of Surface Current by Quantum Tunneling Effect of Thin Film Transistors with Topological Insulators.

Dirac insulator and Weyl conductors have different semiconductor structures. A Dirac insulator is a SiOC insulated thin film, and a Weyl conductor consists of transistors with different semiconductor structures combining channels with SiOC insulated films. The transfer characteristics of transistors were investigated in this study. The difference between Dirac insulators and Weyl conductors is the same as the difference between transistors without channels and transistors with channels. Transistors without channels exhibit bidirectional transmission characteristics due to the spin currents of the Dirac insulators. By contrast, transistors with channels display unidirectional transmission characteristics consistent with the movement of the charges in the channels. This unidirectional transmission characteristic results in an existence of the threshold voltage and leakage current.

Transparent Bipolar Thin Film Transistors Based on Topological Insulator of Magneto-Resistive Effect.

Thin film transistors using SiOC insulation film generated a very large IDS current with tunneling phenomena due to the occurrence of space charge limit current due to magnetic resistance effect. When SiOC gate insulation barrier transistor characteristics were investigated, transmission characteristics of bi-directional were observed, low current at levels ~10-7 A, but switching characteristics were superior to or greater than 10-10 A. SiOC Thin Film Insulation Characteristics are a good material for observing magnetic resistance effects, SiOC Transistors without channels clearly demonstrate the difference in spatial charges due to electromagnetic phenomena, and even in low-current insulation, nano-current flows at high speed. The current due to magnetic resistance is bi-directional and has an alternating current that flows in both directions at 0 V.

Correlation Between Currents, X-ray Diffraction Patterns and Transfer Characteristics of SnO2 Thin Film Transistor.

SnO2 thin film transistor (TFT) was prepared with SiOC as a gate insulator on n-type Si and the correlation between bonding structures, the contact properties of SnO2 thin films and the transfer characteristics of TFTs was researched. The current of SnO2 thin films increased with increasing the crystallinity and the crystallinity of SnO2 was increased by annealing. The SnO2 deposited with much oxygen gas flows became an amorphous structure after annealing due to lowered crystallinity. On the other hand, the current decreased in the amorphous structure SnO2 with high oxygen vacancies. However, the ambipolar transfer characteristics of SnO2/SiOC TFT with an amorphous structure had higher stability-mobility than that of TFT with the crystallinity, because of the increment effect of the diffusion current at the depletion layer as the amorphous structure with high Schottky barrier (SB).

Temperature Dependence of Oxide Semiconductor and Channel Effect of Thin Film Transistor.

ZTO was prepared on SiOC/ITO glass and the electrical characteristics were analyzed in accordance with the annealing temperature to research the temperature dependence and an amorphous structure. SiOC annealed at 150 °C as a gate insulator became an amorphous structure. The ZTO annealed at 150 °C had the capacitance without any variation. However, the capacitance of ZTO on SiOC annealed at 150 °C was increased due to the reduction of energy loss. ZTO/SiOC transistor was observed the ambipolar transfer characteristics with high stability and mobility in accordance with the decrement of drain voltages as a result of tunneling effect. Therefore it was obtained that the SiOC annealed at 150 °C means the highest Schottky barrier (SB) at the interface of ZTO/SiOC as the optimization parameter.

Tunneling Characteristics Depending on Schottky Barriers and Diffusion Current in SiOC.

To obtain a diffusion current in SiOC, the aluminum doped zinc oxide films were deposited on SiOC/Si wafer by a RF magnetron sputtering. All the X-ray patterns of the SiOC films showed amorphous phases. The level of binding energy of Si atoms will lead to an additional potential modulation by long range Coulombic and covalent interactions with oxygen ions. The growth of the AZO film was affected by the characteristics of SiOC, resulting in similar trends in XPS spectra and a shift to higher AZO lattice d values than the original AZO d values in XRD analyses. The charges trapped by the defects at the interlayer between AZO and SiOC films induced the decreased mobility of carriers. In the absence of trap charges, AZO grown on SiOC film such as the sample prepared at O2 = 25 or 30 sccm, which has low charge carrier concentration and high mobility, showed high mobility in an ambipolar characteristic of oxide semiconductor due to the tunneling effect and diffusion current. The structural matching of an interface between AZO and amorphous SiOC enhanced the height of Schottky Barrier (SB), and then the mobility was increased by the tunneling effect from band to band through the high SB.

Depletion effect of oxide semiconductor analyzed by Hall effects.

This letter discusses the tunneling behavior of amorphous indium-gallium-zinc-oxide (a-IGZO) analyzed through the observation of its Hall effects. The properties of the a-IGZO changed from those of a majority carrier to those of a minority carrier after the annealing process as a result of the electron-hole recombination due to the thermal activation energy and the formation of a depletion layer with a high-potential Schottky barrier. Therefore, the diffusion current of these minority charge carriers caused ambipolar transfer characteristics, a tunneling behavior, in the metal-oxide semiconductor (MOS) transistor.

Chemical shift and surface characteristics of Al-doped ZnO thin film on SiOC dielectrics.

Aluminum doped zinc oxide (AZO) films were fabricated on SiOC/p-Si wafer and SiOC film was prepared on a p-type Si substrate with the SiC target at oxygen ambient with the gas flow rate of 5-30 sccm by a RF magnetron sputter. C-V curve of SiOC/Si wafer was measured to observe the relationship between the polarity of SiOC dielectrics and the change of capacitance depending on oxygen gas flow rate. The SiOC film could be controlled to be polar or nonpolar, and their surface energy was changed depending on the polarity. Smooth surface is essential to improve the TFT performance. AZO-TFTs used smooth SiOC film with low polarity as a gate insulator was observed to show low leakage current (IL) and low subthreshold voltage swing. It is proposed that SiOC film with high degree amorphous structure as a gate insulator between AZO and Si wafer could solve problems of the mismatched interfaces, which was originated from the electron scattering due to the grain boundary.

Study on the characteristics of amorphous low-K thin film for solar cells.

The most practical solar cells are silicon based crystal silicon solar cells. Phosphorus oxychloride for n+ type doping was diffused on a p+ Si, SiC and poly Si using N2 carrier gas by low pressure chemical vapor deposition. The series resistances on various p type silicon substrates were researched. An n(+)-p+ junction was fabricated by thermal diffusion of phosphorus oxychloride into a p+ Si wafer. For the rear metallization, Al was deposited using screen printing and SiOC film was used instead of SiO2 film as a passivation material for the metal layer. SiOC film was made by the capacitive coupled plasma chemical vapor deposition. When the Fourier transform infrared spectra of SiOC film shows organic properties including a strong peak of the Si-CH3 bond, the efficiency was increased, because of the reduction of the recombination at the back surface.

Size and usage patterns of private TB drug markets in the high burden countries.

BACKGROUND: Tuberculosis (TB) control is considered primarily a public health concern, and private sector TB treatment has attracted less attention. Thus, the size and characteristics of private sector TB drug sales remain largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: We used IMS Health data to analyze private TB drug consumption in 10 high burden countries (HBCs), after first mapping how well IMS data coverage overlapped with private markets. We defined private markets as any channels not used or influenced by national TB programs. Private markets in four countries--Pakistan, the Philippines, Indonesia and India--had the largest relative sales volumes; annually, they sold enough first line TB drugs to provide 65-117% of the respective countries' estimated annual incident cases with a standard 6-8 month regimen. First line drug volumes in five countries were predominantly fixed dose combinations (FDCs), but predominantly loose drugs in the other five. Across 10 countries, these drugs were available in 37 (loose drug) plus 74 (FDCs) distinct strengths. There were 54 distinct, significant first line manufacturers (range 2-11 per country), and most companies sold TB drugs in only a single study country. FDC markets were, however, more concentrated, with 4 companies capturing 69% of FDC volume across the ten countries. Among second line drugs, fluoroquinolones were widely available, with significant volumes used for TB in India, Pakistan and Indonesia. However, certain WHO-recommended drugs were not available and in general there were insufficient drug volumes to cover the majority of the expected burden of multidrug-resistant TB (MDR-TB). CONCLUSIONS/SIGNIFICANCE: Private TB drug markets in several HBCs are substantial, stable, and complicated. This calls for appropriate policy and market responses, including expansion of Public-Private Mix (PPM) programs, greater reach, flexibility and appeal of public programs, regulatory and quality enforcement, and expansion of public MDR-TB treatment programs.

Sustained release of a p38 inhibitor from non-inflammatory microspheres inhibits cardiac dysfunction.

Cardiac dysfunction following acute myocardial infarction is a major cause of death in the world and there is a compelling need for new therapeutic strategies. In this report we demonstrate that a direct cardiac injection of drug-loaded microparticles, formulated from the polymer poly(cyclohexane-1,4-diylacetone dimethylene ketal) (PCADK), improves cardiac function following myocardial infarction. Drug-delivery vehicles have great potential to improve the treatment of cardiac dysfunction by sustaining high concentrations of therapeutics within the damaged myocardium. PCADK is unique among currently used polymers in drug delivery in that its hydrolysis generates neutral degradation products. We show here that PCADK causes minimal tissue inflammatory response, thus enabling PCADK for the treatment of inflammatory diseases, such as cardiac dysfunction. PCADK holds great promise for treating myocardial infarction and other inflammatory diseases given its neutral, biocompatible degradation products and its ability to deliver a wide range of therapeutics.