FG Elektronenmikroskopie und -holographie

6 Items

Recent Submissions
Simulation of the θ′ Precipitation Process with Interfacial Anisotropy Effects in Al-Cu Alloys

Ta, Na ; Bilal, Muhammad Umer ; Häusler, Ines ; Saxena, Alaukik ; Lin, Yueh-Yu ; Schleifer, Felix ; Fleck, Michael ; Glatzel, Uwe ; Skrotzki, Birgit ; Darvishi Kamachali, Reza (2021-03-08)

The effects of anisotropic interfacial properties and heterogeneous elasticity on the growth and ripening of plate-like θ′-phase (Al2Cu) in Al-1.69 at.% Cu alloy are studied. Multi-phase-field simulations are conducted and discussed in comparison with aging experiments. The precipitate/matrix interface is considered to be anisotropic in terms of its energy and mobility. We find that the additio...

Untersuchung und Anwendung der dynamischen Beugung an inhomogenen Verschiebungsfeldern in Elektronenstrahlrichtung in Halbleiterheterostrukturen

Niermann, Laura (2021)

In dieser Arbeit wird der Einfluss des dynamischen Beugungsverhalten bei inhomogenen Verschiebungsfeldern in Elektronenstrahlrichtung auf die gebeugte Elektronenwelle experimentell und theoretisch untersucht. Die Dunkelfeldphase der gebeugten Elektronenwelle ist sensitiv auf das Verschiebungsfeld. Unter dynamischen Beugungsbedingungen ist dabei kein linearer Zusammenhang zwischen der Dunkelfeld...

Microscopic investigations of inhomogeneities and metastable effects in Cu(In,Ga)Se2 solar cells

Nikolaeva, Aleksandra (2020-09-15)

Although Cu(In,Ga)Se2 (CIGS) thin- film solar cells exhibit power conversion effciencies of more than 23%, there are still open questions concerning factors limiting the photovoltaic performance of the record devices. Band-gap and electrostatic potential fuctuations can be considered as possible reasons of deteriorated photovoltaic performance of CIGS solar cells via enhanced recombination. In ...

Influence of mixed phases on the optoelectronic properties of Cs-Pb-Br compounds

Caicedo Davila, Sebastian (2020)

The current dissertation presents a correlative approach to investigate the influence of phase mixture on the optical properties of Cs–Pb–Br compounds. This material system exhibits three ternary phases, CsPbBr3, Cs4PbBr6 and CsPb2Br5, which coexist in Cs–Pb–Br materials when deposited by various methods. The coexistence influences the light emission and by extension can affect the performance ...

Thickening of T1 Precipitates during Aging of a High Purity Al−4Cu−1Li−0.25Mn Alloy

Häusler, Ines ; Kamachali, Reza Darvishi ; Hetaba, Walid ; Skrotzki, Birgit (2018-12-21)

The age hardening response of a high-purity Al–4Cu–1Li–0.25Mn alloy (wt. %) during isothermal aging without and with an applied external load was investigated. Plate shaped nanometer size T1 (Al2CuLi) and θ′ (Al2Cu) hardening phases were formed. The precipitates were analyzed with respect to the development of their structure, size, number density, volume fraction and associated transformation ...

Off-Axis Electron Holographic Focal Series of GaN

Niermann, Tore (2014)

This is a high resolution off-axis electron hologram series obtained with a transmission electron microscope of a Gallium Nitride (GaN) crystal in <11-20> zoneaxis orientation at atomic resolution. It contains the raw data of two holographic focal series obtained under equal conditions (no strong changes in illumination or microscope setup) a few minutes apart. The first series is a focal serie...