Plastically deformed Ge-crystal wafers that have the cylindrical shape with a large curvature were characterized by neutron diffraction. The box-type rocking curve of Bragg reflection with the angular width of Γbox≃2° in FWHM, which is observable in the monochromatic neutron diffraction, results in an enhancement in the angle-integrated intensity (Iθ). Besides,Iθ efficiently increases by stacking such Ge wafers. In the course of white neutron diffraction, the reflected-beam width near the focus point becomes sharper than the initial beam width. Further, the dependence of the horizontal beam width on the distance between the sample and detector is quantitatively explained by taking account of the large Γbox, the small mosaic spread of η≃0.1°, and the thickness of the wafers. On the basis of these characterizations, use of plastically deformed Ge wafers as elements for high-luminance neutron monochromator is proposed. Keywords Plastically deformed Ge wafer; Neutron monochromator crystal; Neutron beam focus Source:Sciencedirect For more information, please visit our website:www.powerwaywafer.com, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com.
High-power broad-area InGaNAs/GaAs quantum-well (QW) edge-emitting lasers on GaAs substrates in the 1200 nm range are reported. The epitaxial layers of the InGaNAs/GaAs QW laser wafers were grown on n+-GaAs substrates by using metal-organic chemical vapor deposition (MOCVD). The thickness of the InGaNAs/GaAs QW layers is 70 Å/1200 Å. The indium content (x) of the InxGa1−xNyAs1−y QW layers is estimated to be 0.35–0.36, while the nitrogen content (y) is estimated to be 0.006–0.009. More indium content (In) and nitrogen content (N) in the InGaNAs QW layer enables the laser emission up to 1300 nm range. The epitaxial layer quality, however, is limited by the strain in the grown layer. The devices were made with different ridge widths from 5 to 50 μm. A very low threshold current density (Jth) of 80 A/cm2 has been obtained for the 50 μm × 500 μm LD. A number of InGaNAs/GaAs epi-wafers were made into broad-area LDs. A maximum output power of 95 mW was measured for the broad-area InGaNAs/GaAs QW LDs. The variations in the output powers of the broad-area LDs are mainly due to strain-induced defects the InGaNAs QW layers. Source:Sciencedirect For more information, please visit our website:www.powerwaywafer.com, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com.
In the present work, dislocation arrays are investigated in float zone (FZ) grown silicon wafers by the light beam induced current (LBIC) mapping technique at different wavelengths and by deep level transient spectroscopy (DLTS). The LBIC technique appears to be able to recognize and to detect these arrays and to evaluate their recombination strength. In FZ dislocated wafers, a phosphorus diffusion attenuates strongly the LBIC contrast of dislocations, depending on the duration and temperature of the treatment. Electrical activity at room temperature of the defects, still physically present, seems to disappear. Simultaneously, the peak intensity of DLTS spectra related to dislocations is reduced and this evolution depends on the phosphorus diffusion temperature and duration. Keywords Float zone; Recombination strength; Silicon wafers Source:Sciencedirect For more information, please visit our website:http://www.powerwaywafer.com/, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com.
Silicon-on-insulator (SOI) wafer is one of the most appealing platforms for optical integrated circuit with the potential to realize high performance Ultra Large Scale Integration (ULSI) and device miniaturization. In this work, based on simulations to obtain appropriate optical properties of a porous silicon microcavity (PSM), we successfully fabricated a highly efficient PSM on SOI wafer by electrochemical etching for DNA detection at optical wavelength 1555.0 nm. The narrow resonance peak with a full width at half maximum about 26.0 nm in the reflectance spectrum gives a high Q factor which causes high sensitivity for sensing performance. The sensitivity of this sensor is investigated through 19-base pair DNA hybridization in the PSM by surface modification using a standard cross link chemistry method. The red shift of the reflectance spectra shows a good linear relationship with complementary DNA concentration, ranging from 0.625 to 12.500 μM, and the detection limit is 43.9 nM. This optical PSM on SOI is highly sensitive, fast responsive, easy to fabricate and low-costly, that will broadly benefit to develop a new optical label-free biosensor on SOI wafer and has a great potential for biochips based on integrated optical devices. Highlights ► A sensitive label-free PSM biosensor on SOI wafer was fabricated by electrochemical etching. ► By simulations and experiments, we optimized PSM biosensor with a high Q value and a high sensitivity. ► This biosensor was used for DNA detection and red shift shows a good linear relationship with DNA. ► This optical PSM on SOI could be a great potential for biochips based on integrated optical devices. Keywords Silicon-on-insulator wafer; Porous silicon microcavity; DNA biosensor; High sensitivity Source:Sciencedirect For more information, please visit our website:http://www.powerwaywafer.com/, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com.
Highlights •Aberration-corrected TEM and EELS reveal structural and elemental profiles across GaAs/Si bond interfaces in wafer-bonded GaInP/GaAs/Si - multi-junction solar cells. •Fluctuations in elemental concentration in nanometer-thick amorphous interface layers, including the disrubutions of light elements, are measured using EELS. •The projected widths of the interface layers are determined on the atomic scale from STEM-HAADF measurements. •The effects of atom and ion beam activation treatment on the bonding interfaces are assessed quantitatively on the nanometer scale. •The measurements highlight the importance of assessing the influence of interfaces on current-voltage characteristics in multi-junction solar cells [5]. Abstract Aberration-corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) investigations have been applied to investigate the structure and composition fluctuations near interfaces in wafer-bonded multi-junction solar cells. Multi-junction solar cells are of particular interest since efficiencies well above 40% have been obtained for concentrator solar cells which are based on III-V compound semiconductors. In this methodologically oriented investigation, we explore the potential of combining aberration-corrected high-angle annular dark-field STEM imaging (HAADF-STEM) with spectroscopic techniques, such as EELS and energy-dispersive X-ray spectroscopy (EDXS), and with high-resolution transmission electron microscopy (HR-TEM), in order to analyze the effects of fast atom beam (FAB) and ion beam bombardment (IB) activation treatments on the structure and composition of bonding interfaces of wafer-bonded solar cells on Si substrates. Investigations using STEM/EELS are able to measure quantitatively and with high precision the widths and the fluctuations in element distributions within amorphous interface layers of nanometer extensions, including those of light elements. Such measurements allow the control of the activation treatments and thus support assessing electrical conductivity phenomena connected with impurity and dopant distributions near interfaces for optimized performance of the solar cells. Keywords Multi-junction solar cell; Wafer bonding; Interfaces; Aberration corrected STEM/EELS Source:Sciencedirect For more information, please visit our website:http://www.powerwaywafer.com/, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com.
Cubic SiC films (3C–SiC) were deposited on (111) Si substrates by a vapor–liquid–solid tri-phase growth method. In such a process a thin copper layer, which was evaporated on the Si substrate prior to the growth, was melted at high temperature as the flux and then methane (carbon source) was diffused into the liquid layer to react with Si, leading to the growth of SiC on the substrate. Copper showed some good properties as the flux, including high silicon and carbon solubility, low growth temperature and low volatility. Suitable growth parameters to go with the copper flux were identified, under which (111) textured 3C–SiC films were grown. Small numbers of (220) grains were observed to embed in the (111) films, which were difficult to avoid completely. Etching pits of the Cu melt on the substrate surface may act as the preferred sites for the growth of (220) grains. Keywords D. SiC; Liquid phase epitaxy; Thin film Source:Sciencedirect For more information, please visit our website:http://www.powerwaywafer.com/, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com.
Highlights •Nanoscale defects in III–V materials, grown over Si were characterized with CAFM. •The defects exhibit higher conductivity. •The contact rectifying feature is hide by a larger current under the reverse bias. •Patterned samples fabricated using Aspect Ratio Trapping were also characterized. Abstract The implementation of high mobility devices requires growing III–V materials on silicon substrates. However, due to the lattice mismatch between these materials, III–V semiconductors tend to develop structural defects affecting device electrical characteristics. In this study, the CAFM technique is employed for identification and analysis of nanoscale defects, in particular, Threading Dislocations (TD), Stacking Faults (SF) and Anti-phase Boundaries (APB), in III–V materials grown over silicon wafers. Graphical abstract Goal: nanoscale defects, as Threading Dislocations (TD), Stacking Faults (SF), among others, in III–V materials grown over silicon wafers were characterized using a CAFM. The presented results show that the CAFM can help to identify various types of structural defects in III–V materials, as well as measure their conductive characteristic. Source:Sciencedirect Keywords High mobility substrates; III–V semiconductors; Threading Dislocations; CAFM For more information, please visit our website:http://www.powerwaywafer.com/, send us email at sales@powerwaywafer.com or powerwaymaterial@gmail.com.
Thermal Grade Diamand Wafers and Slices Diamond exhibits the highest thermal conductivity among all materials. Its thermal conductivity is up to 2000 W/mK which is higher a lot than that of copper. Therefore diamond wafers and slices become more and more popular in thermal management as heatspreaders,heatsinks, lithographically patterned metallization, electrical isolation between top and bottom metallization, stress relieving slits for stress free mounting etc. CVD diamond heat spreaders in various shapes,and the typical parameters are as follows: Material thermal conductivity >1000 W/mK Diameter Up to 70mm Surface Polished, lapping, as-cut Thickness 100 - 1500 µm Young's modulus 1000-1100Gpa Density 3.5g/cm3 Optical grade diamond wafers Optical grade diamond wafers are used as window for infrared beam splitters, lenses for terahertz spectroscopy and CO2 laser surgery,Brewster Windows for multi-spectral applications such as free electron lasers, multi-wavelength IR lasers or terahertz optical systems,for Units attenuated total reflection) spectroscopy,for diamond Liquid Cells. Source:PAM-XIAMEN For more information, please visit our website: www.semiconductorwafers.net, send us email at luna@powerwaywafer.com or powerwaymaterial@gmail.com.
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