9/9/2023 0 Comments Rheed vs xray diffraction![]() While excellent epitaxial growth has been achieved in GaAs on flexible metal substrates, the defect density of the films as measured by High Resolution X-ray Diffraction and etch pit experiments showed a high value of 5 * 10^8 per cm^2. The GaAs is found to exhibit strong photoluminescence signal and, an existence of a relatively narrow (FWHM~20 meV) band-edge excitons measured in this film indicates a good optoelectronic quality of deposited GaAs. RHEED patterns indicate self annihilation of antiphase boundaries and the growth of a single domain GaAs. GaAs has been successfully grown epitaxially on Ge on metal substrate by molecular beam epitaxy. Refraction index and extinction coefficient values of the Ge films were found to match well with that measured from a reference Ge single crystal. Room temperature optical bandgap of the Ge films was identified at 0.67 eV indicating minimal residual strain. ![]() In spite of a 4.5% lattice mismatch, heteroepitaxial growth of Ge more » was achieved on CeO2 that was grown on IBAD MgO template. MgO templates made by IBAD on flexible metal substrate have been successfully used for epitaxial growth of germanium films. Our program is based on single-crystalline-like thin film photovoltaics on polycrystalline substrates using biaxially-textured templates made by Ion Beam-Assisted Deposition (IBAD). At the other end of the spectrum, polycrystalline and amorphous thin film solar cells offer the advantage of low-cost fabrication, but have not yielded high efficiencies. III-V photovoltaics have exhibited efficiencies above 40%, but have found only a limited use because of the high cost of single crystal substrates. Additional features of the equipment are also presented together with the data taken during typical oxide film growth to illustrate the depth of information available via in situ x-ray techniques. Also two separate thickness monitors are installed. Ozone can be supplied through two separate nozzles for each location. And, the aiming of the evaporation sources is fixed to the point between two locations. Deposition of films was made possible at the two diagnostic positions. In the original design, electron diffraction was intended for the secondary diagnostics available without the necessity of the x-ray more » and located at separate positions. X-ray diffraction has been used as a major probe for film growth and structures for the system. CF (ConFlat, a registered trademark of Varian, Inc.) flange. For oxide MBE growth, pure ozone delivery to the chamber has been made available, and several new deposition sources have been made available on a new 12 in. In situ studies of oxide molecular beam epitaxy by synchrotron x-ray scattering has been made possible by upgrading an existing UHV/molecular beam epitaxy (MBE) six-circle diffractometer system. Publication Date: Research Org.: Argonne National Laboratory (ANL), Argonne, IL (United States) Sponsoring Org.: USDOE Office of Science (SC), Basic Energy Sciences (BES) Contributing Org.: Northwestern Univ., Evanston, IL (United States) OSTI Identifier: 1356978 Alternate Identifier(s): OSTI ID: 1234176 Grant/Contract Number: AC02-06CH11357 Resource Type: Journal Article: Accepted Manuscript Journal Name: Review of Scientific Instruments Additional Journal Information: Journal Volume: 87 Journal Issue: 1 Journal ID: ISSN 0034-6748 Publisher: American Institute of Physics (AIP) Country of Publication: United States Language: English Subject: 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY 36 MATERIALS SCIENCE Thin film growth Reflection high energy electron diffraction Molecular beam epitaxy Vacuum chambers X-ray = , Advanced Photon Source Northwestern Univ., Evanston, IL (United States). Finally, additional features of the equipment are also presented together with the data taken during typical oxide film growth to illustrate the depth of information available via in situ x-ray techniques. ![]() In the original design, electron diffraction was intended for the secondary diagnostics available without the necessity of the x-ray and located at separate positions. ![]()
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