Time Resolved Micro Photoluminescence of InGaN/GaN Quantum Dots

• Main Author: Eriksson, Martin
• Format: Others
• Language: English
• Published: KTH, Skolan för informations- och kommunikationsteknik (ICT) 2011
• Subjects: Engineering physics; Teknisk fysik
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32364

Time resolved micro photoluminescence of InGaN/GaN quantum dots has been investigated, together with power dependence and polarization measurements. The quantum dots are formed at the top of selectively grown GaN pyramids on a 4H-SiC substrate. Decay time constants in the range of 400 ps to 1.1 ns have been observed with a pulsed 267 nm laser with an average power of 20 μW, and no correlation between emission energy and lifetime has been observed. Strong and sharp emission peaks show mono-exponential or close to mono-exponential decay curves and the smaller and/or broader peaks show multi-exponential decays. Different directions of polarization have been observed for two groups of emission peaks, separated by 60°, which fits the six fold symmetry of the pyramids well. Small differences in power dependence and carrier lifetimes have also been observed when comparing these two groups of emission peaks. Selectively grown InGaN/GaN quantum dots can be used for emitters and sensors with customizable wavelength, sharp line width and quick response times in the ultraviolet, blue, and green regions of the electromagnetic spectrum.