Design of Reconfigurable Micro fluidic Met surface with Different Semiconductor Alloys

In this work, design of a reconfigurable metasurface using all-dielectric materials is presented. An elliptical all-dielectric microfluidic-based metasurface is designed using Rogers RO3210 substrate (ε = 10.2 and tan δ = 0.03). The substrate is covered with microfluidic channel which is filled with five various AgTiTe2, Cu2S, Te.5 Se.5, CuTSe2 and Cu3SbSe4. semiconductor alloys. The reflection and transmission characteristics of the designed metasurface are analyzed in the frequency range of 20-30 GHz using COMSOL Multiphysics software. The results demonstrate that change in the semiconductor alloy in the microfluidic channel various the dynamic transmission and reflection characteristics of the metasurface and thus depicts a reconfigurable operation of the proposed design.

B4/32Ga28/32Sb10/32As22/32 Three-Dimensional Semiconductor Superlattice

Self-assembly of BD -rich A x B 1-x C y D 1-y was studied for a lot of semiconductor alloys. An occurrence of identical clustersshould be due to a decrease of the bond energy, internal strain energy or both of them. An arrangement of the clusters is disordered since the contents of minority atoms are in the dilute or ultra dilute limits in the considered alloys. B 4/32 Ga 28/32 Sb 10/32 As 22/32 semiconductor alloy with the three-dimensional superlattice is presented. This superlattice should be stable against disordering due to its minimal free energy. The superlattice forms by the identical cubic units consisting of 64 atoms and is the three-dimensional semiconductor soft X-ray diffraction grating.

Dendritic Growth in Si1−xGex Melts

We investigated the types of dendrites grown in Si1−xGex (0 < x < 1) melts, and also investigated the initiation of dendrite growth during unidirectional growth of Si1-xGex alloys. Si1−xGex (0 < x < 1) is a semiconductor alloy with a completely miscible-type binary phase diagram. Therefore, Si1−xGex alloys are promising for use as epitaxial substrates for electronic devices owing to the fact that their band gap and lattice constant can be tuned by selecting the proper composition, and also for thermoelectric applications at elevated temperatures. On the other hand, regarding the fundamentals of solidification, some phenomena during the solidification process have not been clarified completely. Dendrite growth is a well-known phenomenon, which appears during the solidification processes of various materials. However, the details of dendrite growth in Si1−xGex (0 < x < 1) melts have not yet been reported. We attempted to observe dendritic growth in Si1−xGex (0 < x < 1) melts over a wide range of composition by an in situ observation technique. It was found that twin-related dendrites appear in Si1−xGex (0 < x < 1) melts. It was also found that faceted dendrites can be grown in directional solidification before instability of the crystal/melt interface occurs, when a growing crystal contains parallel twin boundaries.

Non-isothermal phase-field simulations of laser-written in-plane SiGe heterostructures for photonic applications

Advanced solid-state devices, including lasers and modulators, require semiconductor heterostructures for nanoscale engineering of the electronic bandgap and refractive index. However, existing epitaxial growth methods are limited to fabrication of vertical heterostructures grown layer by layer. Here, we report the use of finite-element-method-based phase-field modelling with thermocapillary convection to investigate laser inscription of in-plane heterostructures within silicon-germanium films. The modelling is supported by experimental work using epitaxially-grown Si0.5Ge0.5 layers. The phase-field simulations reveal that various in-plane heterostructures with single or periodic interfaces can be fabricated by controlling phase segregation through modulation of the scan speed, power, and beam position. Optical simulations are used to demonstrate the potential for two devices: graded-index waveguides with Ge-rich (>70%) cores, and waveguide Bragg gratings with nanoscale periods (100–500 nm). Periodic heterostructure formation via sub-millisecond modulation of the laser parameters opens a route for post-growth fabrication of in-plane quantum wells and superlattices in semiconductor alloy films.

Non-Vacuum Fabrication of Bandgap-Controlled CZTGS Alloy Films Using CZTS+CZGS Mixed Nanoparticle Inks

Semiconductor alloy films of Cu2ZnSn1-xGexS4 (CZTGS) were prepared by deposition and sintering of mixed nanoparticle suspensions composed of Cu2ZnSnS4 (CZTS) and Cu2ZnGeS4 (CZGS) nanoparticles with 1-dodecanethiol surfactant. Colloidal CZTS and CZGS nanoparticles were synthesized via the liquid-phase route and used without post-processing treatment. The CZTGS films are crystallized in the form of kesterite structures and form an alloy of CZTS and CZGS without an apparent phase separation. The Sn/Ge ratios in the alloy films were finely controlled by tuning a mixing ratio between CZTS and CZGS nanoparticles. The bandgap energy of the CZTGS film systematically increased from 1.6 to 2.1 eV as the Ge-substitution for Sn in the films proceeded, which indicates the potential of the fabrication method in the manufacture of bandgap-tuned multinary semiconductor thin films.