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Rutile structure of TiO2 thin films grown on Ge (001) substrates by molecular beam epitaxy

Students & Supervisors

Student Authors
Priom Barua
BSc in Electrical & Electronic Engineering, FE
Supervisors
Dr. Md. Nurul Kabir Bhuiyan
Senior Assistant Professor, Faculty, FST

Abstract

Rutile Structure of TiO2 Thin Films Grown on Ge (001) Substrates by Molecular Beam Epitaxy Priom Barua,1* Md. Nurul Kabir Bhuiyan,1,2 Mariela Menghini,2 Maria Seo,3 and Jean-Pierre Locquet2 1Department of Physics, American International University-Bangladesh, 408/1, Kuratoli Road, Khilkhet, Dhaka 1229, Bangladesh 2Department of Physics and Astronomy, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium 3Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001, Leuven, Belgium *Email: priombaruaa@gmail.com The rutile structure of TiO2 has a very high dielectric constant that is a potential material to be used as a gate oxide in CMOS devices [1]. TiO2 thin films were grown on Ge (001) substrates at temperatures of 300°C, 400°C and 450°C by molecular beam epitaxy (MBE). The structural property and surface morphology of TiO2 thin films are analyzed by in situ reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), and atomic force microscopy (AFM) etc. RHEED patterns show that the surface of the TiO2 thin films is smooth but may form facets. XRD peaks for TiO2 thin films grown at 400°C are observed at 2θ =19.45° and 39.30° corresponding to the (100) and (200) diffractions [2]. The interplanar spacing corresponding to the (100) and (200) diffractions are determined to be 4.5583 Å and 2.2898 Å, respectively. Hence, the lattice parameters are estimated to be a = b = 4.56 Å or a = b = 4.58 Å. These findings confirm that the tetragonal rutile TiO2 structure is formed for all samples, which satisfies the bulk value of a = b = 4.584 Å [3]. The scanning area and the z-height range of the AFM images of the TiO2 thin film grown at 400°C are 1 µm × 1 µm and 8.0 nm, respectively. The surfaces of the TiO2 thin films at the growth temperatures of 300°C, 400°C and 450°C are flat and smooth with root mean square (rms) roughnesses of 4.16 Å, 3.87 Å, and 8.75 Å, respectively.

Keywords

TiO2 thin film Ge (001) substrate MBE RHEED XRD AFM

Publication Details

  • Type of Publication: Conference
  • Conference Name: International Conference on Physics-2024
  • Date of Conference: 05/09/2024 - 05/11/2024
  • Venue: Atomic Energy Centre, Dhaka 1000, Bangladesh
  • Organizer: Bangladesh Physical Society
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