ISBN 9783843908306

978-3-8439-0830-6, Reihe Elektrotechnik

Christopher Kölper
Optoelectronic Properties of GaN Nanorods and Light Emitting Diodes

162 Seiten, Dissertation Universität Kassel (2012), Softcover, A5

Zusammenfassung / Abstract

Indium gallium nitride (InGaN)-based light emitting diodes (LEDs) have seen a tremendous increase in output power over the past years. Their internal quantum efficiency (IQE), however, is still limited and decreases with increasing current density ('efficiency droop') and increasing emission wavelength ('green gap'). In this thesis a numerical model is developed and applied to evaluate the efficiency potential of novel nanorod (NR)-based LED concepts, which offer promising approaches to overcome both of these issues. Core-shell NR LEDs, on the one hand, feature significantly increased active areas. The gain in IQE due to lower local current densities mitigates the efficiency droop, but is partly compensated by re-absorption losses in non-polar quantum wells. Strain relaxation in thin quantum disc NRs, on the other hand, allows overcoming the green gap and enables highly efficient phosphorless monolithic white LEDs, based solely on the InGaN material system.