|
|
Imaging Reflectometry Measuring Thin Films Optical Properties
Běhounek, Tomáš ; Spousta, Jiří (referee) ; Zicha,, Josef (referee) ; Kotačka, Libor (referee) ; Druckmüller, Miloslav (advisor)
V této práci je prezentována inovativní metoda zvaná \textit{Zobrazovací Reflektometrie}, která je založena na principu spektroskopické reflektometrie a je určena pro vyhodnocování optických vlastností tenkých vrstev .\ Spektrum odrazivosti je získáno z map intenzit zaznamenaných CCD kamerou. Každý záznam odpovídá předem nastavené vlnové délce a spektrum odrazivosti může být určeno ve zvoleném bodu nebo ve vybrané oblasti.\ Teoretický model odrazivosti se fituje na naměřená data pomocí Levenberg~-~Marquardtova algoritmu, jehož výsledky jsou optické vlastnosti vrstvy, jejich přesnost, a určení spolehlivosti dosažených výsledků pomocí analýzy citlivosti změn počátečních nastavení optimalizačního algoritmu.
|
|
|
Improvement of IBAD apparatus
Urbánek, Ivan ; Nebojsa, Alois (referee) ; Spousta, Jiří (advisor)
This thesis is divided into three main parts dealing with ion beam assisted deposition. In the first part there is a brief description of the IBAD chamber at Institute of Physical Engineering of BUT. There is also a detailed description of control of the IBAD apparatus during deposition. Next part deals with measuring of deposition rates of ion sputtering in order to refine deposition of thin layers. Last part deals with planned and already finished changes that should improve quality and speed of thin layers deposition. Changes include the option of covering the substrate holder, change of the entry flange, design of new insertion chamber with multifunctional substrate holder and the option to control the deposition by computer.
|
|
|
Measurement of thin films properties by imaging spectroscopy and magnetooptical Kerr effect
Plšek, Radek ; Navrátil, Karel (referee) ; Spousta, Jiří (advisor)
This thesis is divided into three main sections that deal with optical and magnetic thin films properties and their measurements techniques. Principles of the spectroscopic reflectometry and measurements of optical properties are described in the first part. Results of imaging reflectometry are most important. This technique is based on in situ monitoring of optical properties of SiO2 thin films during etching over the area cca 10 × 13 mm2. In next section magnetic properties of thin films and new apparatus built on the Institute of Physical Engineering of BUT are shown. Magnetic properties were observed by longitudinal magneto-optical Kerr effect. The construction of the device is based on a light beam with rectilinear polarization reflected from magnetic material with turned polarization. For investigation of local magnetic properties of microstructures a microscope objective focusing laser beam on the sample is used. The last part of the thesis is aimed on improving of a spin valve structure Co/Cu/NiFe. This work was done within the frame of the Erasmus project in Laboratoire Louis Néel in Grenoble. The goal was to achieve the value of GMR (Giant Magnetoresistance) as high as possible by changing of deposition parameters. This value describes the rate of resistances in different mutual directions of magnetization in trilayers.
|
|
|
SNOM probes with special properties
Slabý, Vít ; Kalousek, Radek (referee) ; Spousta, Jiří (advisor)
This bachelor thesis deals with scanning near-field optical microscopy. With SNOM we examined experimentally the near field of the interference of surface plasmon polaritons (PPP) on plasmonic structures consisting of slits in a metal layer a we discuss the effect of probe characteristics on the measurement results.Effect of few characteristics is simulated numerically. Findings obtained in the previous experiments are used for the construction designing of an experimental device called NanoGIS, which should serve for the nanostructure manufacturing.
|
|
| |
|
| |
|
|
Design of the apparatus for the measurement of the magnetic properties of the micro and nanostructures
Flajšman, Lukáš ; Dubroka, Adam (referee) ; Spousta, Jiří (advisor)
This bachelor's thesis deals with magneto-optic effects with special aim for magneto-optic Kerr effect. Presented description allows us to quantify magneto-optical observables on the basis of measuring the light intensity after the reflection from sample surface. Consequently, we use a simple physical model to unriddle the origin of the optical anisotropy induced by the external magnetic field. In the part, that deals with the design of an aparatus for measuring magneto-optical Kerr effect in longitudinal conformation, we provide necessary information to define a device capable of measuring magneto-optic observables in micro/nano scale. Last chapter i aimed to the achieved results on the thin Co films and on magnetic vortices with lateral dimensions of 1 m.
|
|
|
Preparation and analysis of nanostructures in UHV conditions
Gloss, Jonáš ; Spousta, Jiří (referee) ; Mach, Jindřich (advisor)
Cílem této bakalářské práce bylo skoumání přípravy a analýzy nanostruktur v podmínkách vysokého vakua (VV). Teoretická část klade důraz na gallium nitridové (GaN) nanostruktury. Ty pak byly analyzovány rastrovacím tunelovacím mikroskopem (RTM). Aby bylo možné analyzovat připravené vzorky ve VV RTM, bylo provedeno elektrochemické leptání wolfrámového drátu. Tato práce zhrnuje postup k vytvoření wolfrámových hrotů pro RTM. Kapitola o výrobě wolfrámových hrotů zahrnuje popis princípu elektrochemického leptání. Obrázky vyleptaných hrotů byly provedeny pomocí rastrovacího elektronového mikroskopu. Zaostřování hrotů pak bylo vykonáno fokusovaným iontovým svazkem. V této práci je také představena metoda pro opětovné ostření RTM hrotů elektronovým svazkem, vykonávaná in-situ. Bylo dokázáno, že je možné rutinně obdržet wolfrámové hroty s poloměrem křivosti rádovo v nanometrech.
|
|
| |
|
|
Fabrication of the STM tips - static and dynamic etching method
Jonner, Jakub ; Spousta, Jiří (referee) ; Kostelník, Petr (advisor)
This bachelor thesis deals with the static and dynamic method of electrochemical etching way of fabrication tips for Scanning Tunneling Microscope (STM). This thesis describes basic principles of the mentioned methods and the construction solutions of the etching apparatuses. An extensive set of measurements was performed in order to obtain the main goal of the thesis – to determine the influence of various etching parameters on the process and final product. In case of static method, we used various concentrations of KOH solution, depths of plunge of the wolfram wire in to the etching solution and setpoints of the etching voltage. In case of dynamic method, we used also various concentrations of KOH solution and different settings of the etching solution flow rate and setpoints of the etching voltage. The ideal configuration of the etching parameters is presented at the end of the thesis as well with the comparison of the etching results from both of the eching methods.
|
guest ::
