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The indium and aluminum nitride (In x Al 1-x N) semiconductor material was postulated in 2008 as an excellent candidate to produce solar cells. In this research, amorphous layers of In x Al 1-x N (0.55 ≤ x ≤ 0.60) were synthesized using the RF sputtering magnetron technique, and then studied for their possible use in photovoltaic applications. Physical, structural, morphological, optical, and electrical properties were studied. The amorphousness was checked by XRD difractograms. Samples have very smooth surfaces, with very low roughness values, according to AFM and SEM techniques. Electrical properties of the InAlN films were studied using Van Der Pauw technique and Hall Effect parameters. The volumetric carrier concentration decreases when InN fraction mole increases. The mobility values range between 6 × 10 −2 and 5 × 10 −1  cm 2  V −1  s −1 , which are lower than those obtained for crystalline and polycrystalline samples. The obtained band gap values could be used in both the absorbing layer and the window layer in solar cells (1.9 eV–2.3 eV). Interestingly, this figures of Eg are very close to the previously obtained values for polycrystalline samples. The optical absorption coefficients were high compared to the materials currently used in solar cells (~10 5  cm −1 ). This implies the possibility of using thinner layers in photovoltaic devices based on In x Al 1-x N. [ABSTRACT FROM AUTHOR]

The exact role of Cu in the electrical properties of amorphous oxide semiconductors (AOSs) has been unclear, even though Cu has been the key element for the p-type characteristics of crystalline oxide semiconductors. Here, the dynamic changes, determined by diffusion kinetics, in the effect of Cu on the electrical properties of amorphous InGaZnO (a-IGZO) are revealed. In the early stage of annealing, Cu dominantly diffuses into a-IGZO through the free volume and acts as a mobile electron donor, which generates a resistive switching (RS) behavior related to the conductive filaments (CFs). With further annealing, substitutional Cu becomes predominant via In sites. After annealing, supersaturated Cu forms nonuniform, crystalline CuInO clusters in a-IGZO, which decrease the electrical conductivity of a-IGZO and deteriorate the CF-based RS performance. The findings reveal Cu diffusion mechanisms and the role of Cu in the electrical properties of AOSs dependent on the structural location and provide guidelines for modulating the RS characteristics of AOSs through Cu diffusion control. [ABSTRACT FROM AUTHOR]

The effect of various factors such as temperature, film thickness, and Pb content on the electrical conductivity and switching phenomenon in Se TePb films has been examined and is discussed herein. X-ray diffraction analysis and energy-dispersive x-ray spectroscopy were used to confirm the structure and chemical composition of the films, respectively. The variation of the electrical conductivity σ with Pb addition was correlated with the nature and strength of the Pb bonds in the SeTe matrix. Current-voltage characteristic curves showed two regions of high and low resistance with negative differential resistances, revealing memory-type switching corresponding to an electrothermal model. The applicability of this model was confirmed using the electrical to switching activation energy ratio, as well as the heat dissipation factor. The mean switching voltage was found to be dependent on temperature, film thickness, and composition. The decrease in the switching voltage with Pb addition is analyzed based on the thermal stability variation. [ABSTRACT FROM AUTHOR]

The structures of thermoelectric ZnSb and Zn4Sb3 have been studied extensively as a function of temperature but not in detail as a function of pressure. High pressure single crystal X-ray diffraction data allow structure refinements of ZnSb and Zn4Sb3 up to 12.8(2) GPa and 10.6(2) GPa, respectively, and in contrast to previous reports without any signs of phase transitions. At high pressure a redistribution of Zn in Zn4Sb3 is present, which is distinctly different from the thermal response of the structure. Fitting of an equation of state resulted in bulk moduli of 45(2) and 48(1) GPa for ZnSb and Zn4Sb3, respectively. [ABSTRACT FROM AUTHOR]

The structures of thermoelectric ZnSb and Zn4Sb3 have been studied extensively as a function of temperature but not in detail as a function of pressure. High pressure single crystal X-ray diffraction data allow structure refinements of ZnSb and Zn4Sb3 up to 12.8(2) GPa and 10.6(2) GPa, respectively, and in contrast to previous reports without any signs of phase transitions. At high pressure a redistribution of Zn in Zn4Sb3 is present, which is distinctly different from the thermal response of the structure. Fitting of an equation of state resulted in bulk moduli of 45(2) and 48(1) GPa for ZnSb and Zn4Sb3, respectively. [ABSTRACT FROM AUTHOR]

The bond constraint theory (BCT) dealing with the rigidity caused by bond constraints and the long-range potential fluctuations (LRPF) arising from the defects and heterogeneities in the disordered semiconductors are important for understanding the atomic and electronic properties of amorphous semiconductors. Here, they are applied to the already commercialized GeSbTe (GST) chalcogenide glasses used in the rewritable phase change memory (PCM) devices. The main concern at present is to improve their ability to withstand a large number of phase change cycles, by choosing the right composition. The two considerations (BCT and LRPF) are briefly described and tested on the most commonly used GeSbTe and the nearby compositions. While these considerations provide significant insight into their atomic and electronic structures, the ansatz linking them with the durability of the PCM devices need to be justified by more work. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the effect of surface roughness on the electrical characteristics in amorphous indium–gallium–zinc oxide (a-IGZO) thin-film transistors (TFTs) fabricating high-κ Sm2O3 gate dielectrics, prepared under different annealing temperatures. The high-κ Sm2O3 a-IGZO TFT device annealed at 200°C exhibited better electrical characteristics, including a large field effect mobility of 6.25cm2/Vs, small threshold voltage of 0.79V, low subthreshold swing of 354mV/decade, and high I on/I off ratio of 3.1×107. These results are attributed to the formation of smooth surface at the oxide/channel interface. Furthermore, the reliability of a Sm2O3 a-IGZO TFT device can be improved by oxygen annealing at low temperature. [Copyright &y& Elsevier]

In this paper, we report on the electrical properties of metal-oxide-semiconductor (MOS) capacitors containing a well-confined 8 nm-thick SiGe amorphous layer (a-SiGe) embedded in a SiO2 matrix grown by RF magnetron sputtering at a low temperature (350 ?C). Capacitance-voltage measurements show that the introduction of the SiGe layer leads to a significant enhancement of the charge trapping capabilities, with the memory effect and charge retention time larger for hole carriers. The presented results demonstrate that amorphous floating-gate SiGe layers embedded in SiO2 may constitute a suitable alternative for memory applications. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the mobility enhancement in an Amorphous Oxide Semiconductor Thin Film Transistor (AOS TFT), particularly the effect of enhanced-mobility current path was investigated. In the TFT structure, the a-IGZO single active channel layer was replaced by double layers. Indium Tin Oxide (ITO) was employed as an enhanced-mobility current path material and was embedded in an amorphous Indium Gallium Zinc Oxide (a-IGZO) channel layer of a conventional bottom gate structure TFT. To analyze the effect of the length of an additional current path, the a-IGZO channel length was fixed at 80μm, and the length of the ITO enhanced-mobility current path was increased to 20, 40, and 60μm. As a result, the mobility increased monotonically with the length of the enhanced-mobility current path and was predictable from the rule of mixture. The maximum saturation mobility of 28.3cm2/Vs resulted when the length of the enhanced-mobility current path was 60μm. This value is more than double that of a single path TFT. Such enhancement in mobility is attributed to the high conductivity of ITO and a good conduction band match between a-IGZO and ITO. [Copyright &y& Elsevier]

The article presents a study of the electrophysical properties elemental boron's fine powders, with focus on size effect. It examines the samples of amorphous (a-B), nanosized (n-B), and crystalline (c-B) elemental boron using X-ray powder diffraction. Results suggest that elemental boron powders, particularly amorphous have a combination of electrical properties with high relative permittivity and low electrical conductivity that are likely useful in producing capacitor materials.

We present a simple and semi-physical analytical description of the current–voltage characteristics of amorphous oxide semiconductor thin-film transistors in the above-threshold and sub-threshold regions. Both regions are described by single unified expression that employs the same set of model parameter values directly extracted from measured terminal characteristics. The model accurately reproduces measured characteristics of amorphous semiconductor thin film transistors in general, yielding a scatter of <4\%. [ABSTRACT FROM PUBLISHER]

Electron-beam deposition of an insulating granular aluminium or off-stoichiometric amorphous alumina layer on a SrTiO3 surface is a simple way to get a metallic interface from insulating materials. No heating nor specific preparation of the SrTiO3 surface is needed. In this paper, we investigate how the electrical properties of this interface can be tuned by the use of a back gate voltage (electrical field through the SrTiO3 substrate). We demonstrate that the slow field-effect observed at room temperature can be used to tune in a controlled, reversible way the low temperature electrical properties of the interface. In particular, important parameters of a transistor such as the amplitude of the resistance response to gate voltage changes or the existence of an ‘on’ or an ‘off’ state at zero gate voltage and at low temperature can be adjusted in a single sample. This method should be applicable to any SrTiO3-based interface in which oxygen vacancies are involved and might provide a powerful way to study the metal or superconductor insulator transition observed in such systems. [ABSTRACT FROM AUTHOR]