|
|
Preparation and characterization of MoS2 thin films
Tomková, Renáta ; Zahradníček, Radim (referee) ; Bartoš, Miroslav (advisor)
This thesis deals with topological insulators, which are described by the quantum spin Hall effect, as well as on semiconductors, where the band structure of semiconductors and more specifically mentioned unipolar transistor MOSFET is explained. There are also mentioned primarily 2D materials and in particular of MoS2. Topic focuses on its structure, the electric properties, the use and preparation by using micromechanical exfoliation. In the last chapter it is described how to prepare MoS2 structures and their analysis. Structural properties of this material were measured by the AFM and Raman spectroscopy. The experimental part there are illustrative photograph of MoS2 taken with an optical microscope and spatial structures created by AFM.
|
|
|
Organic semiconductors on topological insulators
Hrubá, Daniela ; Průša, Stanislav (referee) ; Procházka, Pavel (advisor)
This bachelor thesis is focused on the utilization of the topological insulator Bi2Se3 as a substrate for the deposition of different types of organic molecules. The substrate was prepared by exfoliation method under ultrahigh vacuum (UHV) conditions. The pentacene, 4,4'-biphenylcarboxylic acid (BDA), and tetracyanoquinodimethane (TCNQ) molecules were subsequently deposited using effusion cells. The quality and arrangement of the fabricated layers were characterized by low-energy electron microscopy (LEEM). The measured results and the behavior of the molecules on the crystal surface after their deposition are discussed. Diffraction patterns were used for design of real-space molecular arrangement model.
|
|
|
Optical and magneto-optical properties of thin films of topological insulator Bi2Se3
Jambrich, Jakub ; Veis, Martin (advisor) ; Hamrle, Jaroslav (referee)
Topological insulators have attracted intensive research interest in the field of material research in the last two decades. Their main advantage is that metallic conductive states are formed on their surface, in which the electrons can move as if their effective mass is nearly zero. This feature has huge potential for use in the new generation of high-speed electronics. In this work, we investigate the optical and magneto-optical properties of the topological insulator Bi2Se3, which are key to its further potential use. By measuring the absorption at Landau levels in a high magnetic field, we determine the shape of the dispersion of the electronic structure as well as the bandgap. Subsequently, by spectroscopic ellipsometry in the range of the visible and near-ultraviolet spectrum, we measure the energy dependence of complex relative permittivity, which is the key for the description of optical properties.
|
|
|
Preparation and characterization of MoS2 thin films
Tomková, Renáta ; Zahradníček, Radim (referee) ; Bartoš, Miroslav (advisor)
This thesis deals with topological insulators, which are described by the quantum spin Hall effect, as well as on semiconductors, where the band structure of semiconductors and more specifically mentioned unipolar transistor MOSFET is explained. There are also mentioned primarily 2D materials and in particular of MoS2. Topic focuses on its structure, the electric properties, the use and preparation by using micromechanical exfoliation. In the last chapter it is described how to prepare MoS2 structures and their analysis. Structural properties of this material were measured by the AFM and Raman spectroscopy. The experimental part there are illustrative photograph of MoS2 taken with an optical microscope and spatial structures created by AFM.
|
guest ::
