A5032867405- Semiconductor materials and interfaces
- Semiconductor materials and devices
- Silicon and Solar Cell Technologies
- Silicon Nanostructures and Photoluminescence
- Metal and Thin Film Mechanics
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor Quantum Structures and Devices
- Silicon Carbide Semiconductor Technologies
- Thin-Film Transistor Technologies
- Innovative concrete reinforcement materials
- Concrete and Cement Materials Research
- Advanced ceramic materials synthesis
- Magnetic and transport properties of perovskites and related materials
- Electronic and Structural Properties of Oxides
- Advanced Materials Characterization Techniques
- Luminescence Properties of Advanced Materials
- GaN-based semiconductor devices and materials
- Optical Coatings and Gratings
- Wood Treatment and Properties
- Advanced Cellulose Research Studies
- ZnO doping and properties
- Perovskite Materials and Applications
- Diamond and Carbon-based Materials Research
- Lignin and Wood Chemistry
- Nanowire Synthesis and Applications
University of Illinois Urbana-Champaign
2014-2024
Goodwin College
2002-2013
University of Illinois System
2000-2010
Evans Analytical Group (United States)
1997-1998
Linköping University
1991-1997
Thinfilm (Sweden)
1995
Universidade de São Paulo
1989
Single-crystal ZrN films, 830 nm thick, are grown on MgO(001) at 450 °C by magnetically unbalanced reactive magnetron sputtering. The combination of high-resolution x-ray diffraction reciprocal lattice maps, cross-sectional transmission electron microscopy, and selected-area shows that grows epitaxially with a cube-on-cube orientational relationship, (001)ZrN‖(001)MgO [100]ZrN‖[100]MgO. layers essentially fully relaxed parameter 0.4575 nm, in good agreement reported results for bulk...
In situ X‐ray experiments were conducted to examine the electric‐field‐induced phase changes in PZT‐5H materials. The diffraction profiles at different electric‐field levels analyzed by peak fitting and used identify occurrence of non‐180° domain switching transition. We found that depolarized samples, there exists a threshold electric field for changes, whereas polarized no such exists. profound difference profile under positive negative fields samples is responsible asymmetry piezoelectric...
Abstract The objective of this project was to further develop new composites and a testing program for the performance‐based specification natural Amazonian geopolymer (GP) use in ceramics construction. While fly ash‐based alkali activated materials are now an established technology, metakaolin‐based GPs still need be developed optimized regarding knowledge specific characteristics properties local resources. kaolin calcined into metakaolin (AMK). AMK particle size reduction better reactive...
Epitaxial Ti1−xWxN alloys with 0⩽x⩽0.6 were grown on MgO(001) substrates at 500 °C by ultrahigh vacuum reactive magnetron sputtering from Ti and W targets in pure N2. X-ray diffraction, transmission electron microscopy (TEM), cross-sectional TEM show that the 0.3-μm-thick Ti1−xWxN(001) are single crystals B1-NaCl structure. Rutherford backscattering spectroscopy investigations indicate x⩾0.05 slightly overstoichiometric N/(Ti+W)=1.06±0.05. The alloy lattice parameter a⊥ along film growth...
Nb$_3$Sn has great potential to become the material of choice for fabrication SRF cavities. The higher critical temperature potentially allows an increased operational in cavities, which could enable tremendous simplification cryogenic system, leading significant cost reduction. We present extended characterization a coated Nb cavity prepared at Cornell University. Using combination thermometry during RF measurements, and structural analytical cutouts, we discover coating flaws responsible...
Single crystal 3C-SiC films of thickness ∼10 μm were grown by reactive magnetron sputtering on off-axis Si(001) at 850 °C. The film quality was comparable to the best chemical vapor deposited as characterized x-ray diffraction, transmission electron microscopy, and photo- luminescence (PL). lattice mismatch difference in thermal contraction between SiC Si resulted complete arrays misfit dislocations film/substrate interface a residual in-plane strain (−6.9±1)×10−4, respectively. full width...
The microstructure and microchemistry of CoSi2/Si1−xGex/Si(001) heterostructures, in which the Si1−xGex layers were grown by molecular-beam epitaxy (MBE) silicides formed different postdeposition reaction paths, investigated using a combination high-resolution cross-sectional transmission electron microscopy, x-ray diffraction, secondary-ion-mass spectrometry. In two three sample configurations investigated, Co was deposited either (S1) directly on strained layer or (S2) sacrificial MBE Si...
Single-crystal metastable diamond-structure Ge1−xSnx/Ge strained-layer superlattices (SLS) with x up to 0.24 (the equilibrium solid solubility of Sn in Ge is <0.01) have been grown on Ge(001)2×1 substrates using temperature-modulated molecular-beam epitaxy maximum growth temperatures Ts≤150 °C. In situ reflection high energy electron diffraction combined postdeposition high-resolution x-ray (HR-XRD) and cross-sectional transmission microscopy results show that the Ge1−xSnx(001)2×1...
Two-dimensional reciprocal space mapping with high-resolution x-ray diffraction has been used to characterize the strain in as-grown and annealed Sb-doped Si. Si(100) layers Sb concentrations 1×1019–3×1021 cm−3 were grown by molecular-beam epitaxy at a growth temperature of 310 °C. High-resolution transmission electron microscopy applied determine critical thickness for epitaxial growth, morphology, defect structure. The low-temperature decreases increasing concentration from ∼1000 Å...
Large enhancements in the electron mobility are reported for structures containing a pair of closely spaced Sb δ-doped layers Si. The room-temperature is enhanced by factor 2 compared to corresponding uniformly doped singly structures. Even higher mobilities were obtained using Schottky gate on top and applying voltage adjust potential well. With an effective ∼−0.3 V was 1200 cm2 V−1 s−1 at room temperature, which enhancement 10 relative layer with equivalent bulk doping concentration. high...
We report on the structural characterization of CoSi2/n-Si0.9Ge0.1/p-Si heterostructures. Silicon molecular beam epitaxy is combined with Co sputtering to obtain these structures. The strain in Si1−xGex investigated after formation CoSi2 by using high-resolution x-ray diffraction mapping reciprocal space and cross-sectional transmission electron microscopy. results show that order keep unaffected, a sacrificial Si layer needed. It was possible transistor action, but low-current gain (β).
The electrical properties of Schottky junctions on high-quality p-type strained Si1−xGex layers have been studied for Ge fractions 0≤x≤0.24. A multicrystal high-resolution x-ray diffractometer was used to investigate the sample’s quality and strain state accurately determine fraction in fabricated devices. Several different metals, having a wide range barrier heights, were reach conclusions variation height with content grown layers. It has found that decreases increasing layer metals...
B-doped Si1−xGex layers with Ge fractions, determined by Rutherford backscattering spectroscopy, ranging from 0 to 0.28 and B concentrations, quantitative secondary-ion spectroscopy measurements, between 5×1016 4×1019 cm−3 were grown on Si(001) at temperatures Ts=475–575 °C gas-source molecular beam epitaxy Si2H6, Ge2H6, B2H6. Film thicknesses ranged 200 nm for alloys x=0.28 800 x=0.05 1.4 μm Si. Structural analyses high-resolution x-ray diffraction reciprocal lattice mapping combined...
Three-dimensional (3D) photonic crystals are one class of materials where epitaxy, and the resultant attractive electronic properties, would enable new functionalities for optoelectronic devices. Here we utilize self-assembled colloidal templates to fabricate epitaxially grown single crystal 3D mesostructured GaxIn1−xP (GaInP) semiconductor using hydride vapor phase epitaxy (HVPE). The epitaxial relationship between GaInP substrate is preserved during growth through complex geometry template...