Charge carrier dynamics in InGaN quantum wells: Stimulated emission depletion and lateral charge carrier motion

Stimulated emission depletion (STED) and lateral charge carrier motion in InGaN/GaN quantum wells are investigated. The properties of STED are experimentally studied and furthermore analyzed with an extended version of the rate equation system typically used for fluorescence dyes. The temperature and charge carrier density dependence of lateral charge carrier motion is studied by a confocal time of flight method and a 2D version of the ABC model.

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The focus of this work is the investigation of stimulated emission depletion (STED) and lateral charge carrier motion within InGaN/GaN quantum wells of Indium Gallium Nitride (InGaN) based LEDs.
In the first part, the properties of the STED effect in blue InGaN quantum wells are studied and compared to those of dye systems usually used in STED microscopy. Continuous wave and pulsed measurements are discussed and furthermore analyzed with an extended rate equation system based on the one typically used for fluorescence dyes.
A confocal time of flight method is used in the second part to investigate lateral charge carrier motion in blue and turquoise InGaN quantum wells for various charge carrier densities and in the temperature range between 4 K and room temperature. The measurements are analyzed using a 2D version of the ABC model, which includes drift and diffusion of charge carriers within the quantum well plane.