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National Science Foundation GOALI: Epitaxial Growth of Perovskite Films and Heterostructures by Atomic Layer Deposition and Molecular Beam Epitaxy John.

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Presentation on theme: "National Science Foundation GOALI: Epitaxial Growth of Perovskite Films and Heterostructures by Atomic Layer Deposition and Molecular Beam Epitaxy John."— Presentation transcript:

1 National Science Foundation GOALI: Epitaxial Growth of Perovskite Films and Heterostructures by Atomic Layer Deposition and Molecular Beam Epitaxy John G. Ekerdt, University of Texas at Austin, DMR 1006725 A customized atomic layer deposition (ALD) chamber has been integrated with a molecular beam epitaxy (MBE) system, allowing in-situ transfer of samples. This enables the study of epitaxial oxide films grown by ALD on surfaces, grown with MBE, that have different terminations and partial- to-complete layers. Crystalline thin films of titanium dioxide (TiO 2 ), strontium titanate (SrTiO 3 ), and lanthanum aluminate (LaAlO 3 ) have been monolithically integrated on Si(001) by depositing the films with ALD on templates of four units cells of SrTiO 3 grown on Si(001) by MBE. Both TiO 2 and SrTiO 3 (STO) films are crystalline as-deposited, while LaAlO 3 (LAO) films are amorphous and become crystalline after annealing at 600 °C for 2 hrs. The relatively low ALD temperature (250 °C) prevents amorphous SiO x formation at the STO-Si interface. Integration of functional oxide films with Si(001) has potential applications in advanced oxide electronics, hyperspectral sensors, radars, and memristor and spintronic devices. (LEFT) Rocking curve of STO(002) reflection for 22-nm thick STO film grown by ALD; the full-width half maximum (FWHM) is 0.34°, comparable to MBE-grown films No Si-O bonding Si 2p 1/2 Si 2p 3/2 STO (ABOVE) High-resolution transmission electron micrograph of a 10-nm thick LAO film grown by ALD on STO/Si(001) (RIGHT) X-ray photo- electron spectra of the Si 2p, indicating negligible SiO x formation at the STO-Si interface due to ALD Supporting Publications: 1) M. D. McDaniel, et al., Thin Solid Films (2012), doi:10.1016/j.tsf.2012.06.061 2) M. D. McDaniel, et al., J. Vac. Sci. Technol. B 30, 04E111 (2012) STO (002) FWHM = 0.34° LAO

2 National Science Foundation GOALI: Epitaxial Growth of Perovskite Films and Heterostructures by Atomic Layer Deposition and Molecular Beam Epitaxy John G. Ekerdt, University of Texas at Austin, DMR 1006725 (Top) AIW participant presenting a lecture on “Experimenting with Micro-spheres”; (bottom) the 2012 AIW students in the Materials Physics Lab We have continued the Demkov-initiated outreach Program Alice in Wonderland (AIW), initially funded under the NSF grant DMR-0606464. The program is aimed at attracting high-school female students to physical sciences and engineering; in collaboration with the physics instructors in local high schools, the students spend summers in research groups at the University of Texas at Austin and participate in “real science” in a supportive environment. The program has two parts, the summer camp and labs. After the summer camp is finished, the AIW participants work in their chosen research groups for a month or longer. Students learn from the hands on experience about advanced subjects such as a single spin detection, optical properties of nanoparticles, magnetic atomic force microscopy (AFM), atomic layer deposition (ALD) growth of thin films, biophysics, and first principles calculations. They interact with a large group of faculty, graduate and undergraduate students.


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