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The development of high energy density materials (HEDMs) with balanced detonation energy and sensitivity is an urgent task in the current energetic material field. Here, by means of density functional theory (DFT) computations, we systematically exploited 14 cyclic nitramines in the framework of 1,3,5-trinitro-1,3,5-triazine (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) as HEDMs. Our results demonstrate that although the -CF(NO2)2 derivatives exhibit negative heats of formations; all designed compounds have high crystal densities (1.83–2.09 g/cm3), good thermal stability (bond dissociation energy > 143 kJ/mol), and remarkable detonation performance (detonation velocities, 8.59–9.31 km/s). More importantly, compounds A1, B1, C1, and D1 exhibit lower impact sensitivity than 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20). Given these properties, it could be expected that compounds A1, B1, C1, and D1 are potential HEDM candidates with acceptable sensitivity. [ABSTRACT FROM AUTHOR]

We investigate thermally induced instability of thin film transistors with incorporating sputtered InZnO and InGaZnO as the channel layer at room temperature, using density of states extracted from temperature-dependent field-effect measurements method and falling rates of activation energy. The trends between density of states and stability under temperature stress are entirely consistent with each other in respect of the reduction of total traps with different channel layer. Moreover, the instability for InGaZnO based TFTs and InZnO based TFTs has been investigated under positive gate bias stress, and the device with InGaZnO channel layer shows a slighter positive threshold voltage shift than that of InZnO based device under positive bias stress. This result demonstrates that the stability of the device is closely related with the density of states. [ABSTRACT FROM AUTHOR]

In this paper, we have fabricated the magnesium-doped indium oxide (MgInO) thin-film transistors (TFTs) by solution process and evaluate the electrical characteristics and stability under temperature stress and positive bias stress. The MgInO TFTs show a decrease of off-state current ( \text I{\mathrm{\scriptscriptstyle off}}) and an increase of threshold voltage ( \text V\mathrm {TH}) with the increase of Mg doping concentration. For MgInO TFT with 0.75 mol% Mg doping concentration, it shows an excellent electrical characteristic (the field effectmobility of 13.77 cm ^2 \text V^-1~\texts^-1 , the threshold voltage of 2.84 V, and subthreshold swing value of 0.85 V/decade) and a good stability of temperature stress and positive bias stress. The performance enhancement of MgInO TFTs is attributed to the reduced density of states and the lower interface trap density by the optimized Mg doping concentration, which is first verified by the temperature-dependent field effect measurement and capacitance–voltage method. [ABSTRACT FROM PUBLISHER]

Double-channel structure HfZnSnO/ZnSnO thin-film transistors (HZTO/ZTO TFTs) with a high electrical property and a superior stability under negative bias illumination stress (NBIS) or temperature stress (TS) is fabricated by cosputtering. Double-channel structure HZTO/ZTO TFT only suffers from 1.4 V negative threshold voltage shift ( \Delta VT) under the same NBIS and 6.3 V negative \Delta VT under the same TS, but its mobility can also stay appropriately 8 cm ^\mathrm 2 /Vs. The high performance, superior NBIS stability, and superior TS stability of HZTO/ZTO TFT are due to the effect of Hf doping on suppression of oxygen vacancies in HZTO top channel layer and high carrier concentration in a ZTO bottom channel layer, which can be confirmed by X-ray photoelectron spectroscopy (XPS) measurement and Hall effect measurement. In addition, based on the measurement of I\mathrm{ DS} – VG under various temperatures, the density of states (DOS) can be extracted from thermally excited drain current. The HZTO/ZTO TFT shows fewer DOSs than that of single ZTO TFT, and it is comparable with that of single HZTO TFT. This result can be well matched with the TS stability, NBIS stability, and XPS measurement. [ABSTRACT FROM AUTHOR]

In this paper, the highly improved negative bias illumination stress (NBIS) stability of zinc-tin-oxide (ZTO) thin-film transistors (TFTs) is achieved by Hf doping, using dual-target magnetron cosputtering system. Compared with a large negative threshold voltage shift ( \vartriangle VT) of 9 V in pristine ZTO TFT, the Hf-doped ZTO TFTs shows superior stability and device D only shows 1.9 V negative \vartriangle VT under the same NBIS. The enhancement in NBIS stability of Hf-doped ZTO TFTs is attributed to a lower oxygen vacancy concentrations and a fewer interface trap states suppressed by Hf ion. The decrease of oxygen vacancy concentrations and interface trap states are confirmed by X-ray photoelectron spectroscopy measurement and capacitance voltage ( $C$ – $V$ ) measurement, respectively. It is consistent with trap density extracted from temperature-dependent field-effect measurements, which verifies further the factor of the improvement of in NBIS stability of Hf-doped ZTO TFTs. [ABSTRACT FROM AUTHOR]

Seismic tomography models have revealed that there exist two large low shear velocity provinces (LLSVPs) beneath Africa and the Pacific Ocean in the Earth's lower mantle. Waveform modeling results suggest both LLSVPs have steep sharp side boundaries, which imply that they probably are compositionally heterogeneous from the ambient mantle. When applying the surface plate motion history in the last a few hundred million years (Ma) as the driving mechanism, numerical modeling has successfully reproduced the geographical distribution of the two LLSVPs in thermochemical mantle convection. However, two prominent seismic features of the LLSVPs, the steep side boundaries and the high elevation, can hardly be obtained in previous geodynamic models. Here, we include in our mantle convection model the effects of iron-spin transition of ferropericlase which substantially change physical properties of the mantle. Our results show that iron-spin transition plays a dominant role in controlling the structure and stability of LLSVPs. Large chemical blocks with steep side boundaries and high elevations up to ∼1200 km above core–mantle boundary (CMB) emerge in our models with the volume content of ferropericlase ∼20%. Such blocks cause a shear wave velocity decrease of ∼3.5% which is consistent with the seismic observations. Our results also show that these LLSVPs are transient structures in the lower mantle, which can typically last for a few hundred million years before destroyed by large-scale mantle motion. [ABSTRACT FROM AUTHOR]

Fluoropolymers have been widely used as oxidizers. In this study, poly(vinylidene fluoride) was employed to oxidize nanoaluminum, and the thermal behavior was investigated by thermogravimetry combined with differential scanning calorimetry and mass spectrometry. The results show that the addition of nanoaluminum significantly decreased the thermal stability of poly(vinylidene fluoride) and that the decomposition of nanoaluminum/poly(vinylidene fluoride) occurred in two temperature ranges. The first from 200 to 280 degree Celsius involved the decomposition of adsorbed water on the nanoaluminum and the reaction of the alumina shell on the surface and dissociative fluoride. The second from 350 to 450 degrees Celsius involved the degradation of poly(vinylidene fluoride) and reaction of nanoaluminum and gas products from the polymer and its matrix. The kinetic process was divided into four steps with apparent activation energies calculated by Kissinger method of 137, 182, 163, and 176 kilojoules per mole, respectively. From evolved gas product analysis, the fluorinated products were identified from the decomposition of poly(vinylidene fluoride) and nanoaluminum/ poly(vinylidene fluoride) composites. However, the intensities of fragments from nanoaluminum/poly(vinylidene fluoride) were lower than those from pure poly(vinylidene fluoride). Other decomposition products included H2, H2O, and OH. [ABSTRACT FROM PUBLISHER]

Abstract Boron doped InZnO (BIZO) thin film has been fabricated via solution process and the effect of boron addition on the properties of BIZO thin film is investigated with the glancing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), the atomic force microscopy (AFM) and UV–vis spectrophotometer. The XPS spectra show that the oxygen vacancies in IZO semiconductor materials are effectively suppressed by boron contents due to high Lewis acid strength and strong bonding dissociation energy of B O. Moreover, the associated application in TFTs has also been fabricated by solution process and the thermal stability and electrical properties of solution processed BIZO-TFTs are investigated to confirm the decrease of oxygen vacancies in IZO materials. Meanwhile, the capacitance voltage measurement and the density of states are carried out to further investigate the enhanced electrical performance and thermal stability of TFTs due to the suppression of oxygen vacancies. Thus, the B doping is an effective method to suppress the generation of oxygen vacancies in IZO materials and to improve the thermal stability of solution processed BIZO-TFTs. Highlights • Influence of boron composition on oxygen vacancy of BInZnO thin films. • Thermal stability of BInZnO TFTs. • Solution processed BIZO thin films and BIZO-TFTs. • CV measurement and the DOS. [ABSTRACT FROM AUTHOR]