Relations between compositional modulation and atomic ordering degree in thin films of ternary Ⅲ-Ⅴ semiconductor alloys

This paper derives the expressions for the ordering degree and the modulation factor of A and B atoms in AXB1-xC epilayers of ternary III-V semiconductor alloys. Using these expressions, it identifies quantitatively the alternating atom-enhanced planes, compositional modulations, atomic ordering degree on the group-III sublattices and the fine structure of NMR spectra.

ZnO_(1-x)Te_x and ZnO_(1-x)S_x semiconductor alloys as competent materials for opto-electronic and solar cell applications:a comparative analysis

ZnO1-xTex ternary alloys have great potential to work as a photovoltaic （PV） absorber in solar cells. ZnOl-xSx is also a ZnO based alloy that have uses in solar cells. In this paper we report the comparative study of various parameters of ZnO 1-x Tex and ZnO 1-x Sx for selecting it to be a competent material for solar cell applica- tions. The parameters are mainly being calculated using the well-known VCA （virtual crystal approximation） and VBAC （Valence Band Anti-Crossing） model. It was certainly being analysed that the incorporation of Te atoms produces a high band gap lower than S atoms in the host ZnO material. The spin-orbit splitting energy value of ZnOl-xTex was found to be higher than that of ZnOl-xSx. Beside this, the strain effects are also higher in ZnO^-xTex than ZnOl-xSx. The remarkable notifying result which the paper is reporting is that at a higher per- centage of Te atoms in ZnOl-xTex, the spin-orbit splitting energy value rises above the band gap value, which signifies a very less intemal carrier recombination that decreases the leakage current and increases the efficiency of the solar cell. Moreover, it also covers a wide wavelength range compared to ZnO1-x Sx.

Positron Affinity, Deformation Potential and Diffusion Constant in AlxIn1-xSb Ternary Semiconductor Alloys

The present investigation deals with the positron behaviour in Alxlnl_xSb ternary semiconductor alloys in the zinc-blende phase. The calculations are mainly based on a pseudopotential approach coupled with the independent particle model. Features such as elastic constants, electron and positron chemical potentials, positron deformation potential and positron diffusion constant are determined. Moreover, the positron affinity to InSb, A1Sb and their related ternary alloys and heterostructures is calculated. The present results are compared to experiment and found to be in reasonably good agreement. The information gathered from the present study can help in understanding the positron trapping at interfaces and precipitates and might be useful in slow-positron-beam experiments.

Multiple radial phosphorus segregations in GaAsP core-shell nanowires

Highly faceted geometries such as nanowires are prone toform self-formed features,especially those that are driven by segregation.Understanding these features is important in preventing their formation,understanding their effects on nanowire properties,or engineering them for applications.Single elemental segregation lines that run along the radii of the hexagonal cross-section have been a common observation in alloy semiconductor nanowires.Here,in GaAsP nanowires,two additional P rich bands are formed on either side of the primary band,resulting in a total of three segregation bands in the vicinity of three of the alternating radii.These bands are less intense than the primary band and their formation can be attributed to the inclined nanofacets that form in the vicinity of the vertices.The formation of the secondary bands requires a higher composition of P in the shell,and to be grown under conditions that increase the diffusivity difference between As and P.Furthermore,it is observed that the primary band can split into two narrow and parallel bands.This can take place in all six radii,making the cross sections to have up to a maximum of 18 radial segregation bands.With controlled growth,these features could be exploited to assemble multiple different quantum structures in a new dimension(circumferential direction)within nanowires.

Dual-channel type tunable field-effect transistors based on vertical bilayer WS2(1−x)Se2x/SnS2 heterostructures

Layered semiconductor heterostructures are essential elements in modern electronic and optoelectronic devices.Dynamically engineering the composition of these heterostructures may enable the flexible design of the properties of heterostructure-based electronics and optoelectronics as well as their optimization.Here,we report for the first time a two-step chemical vapor deposition approach for a series of WS2(1−x)Se2x/SnS2 vertical heterostructures with high-quality and large areas.The steady-state photoluminescence results exhibit an obvious composition-related quenching ratio,revealing a strong coherence between the band offset and the charge transfer efficiency at the junction interface.Based on the achieved heterostructures,dual-channel backgate field-effect transistors were successfully designed and exhibited typical composition-dependent transport behaviors,and pure n-type unipolar transistors to ambipolar transistors were realized in such systems.The direct vapor growth of these novel vertical WS2(1−x)Se2x/SnS2 heterostructures could offer an interesting system for probing new physical properties and provide a series of layered heterostructures for high-quality devices.