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HL: Fachverband Halbleiterphysik

HL 95: Poster IV B (Quantum dots and wires: Prepration, characterization, optical properties, and transport)

HL 95.21: Poster

Donnerstag, 19. März 2015, 14:00–20:00, Poster B

Time-resolved photoluminescence of silicon nanoparticles — •Robert Niemöller, Daniel Braam, Günther M. Prinz, Martin P. Geller, and Axel Lorke — Experimentalphysik und CENIDE, Universität Duisburg-Essen

Bulk silicon is a poor light emitter, due to its indirect band-gap, hindering optical device integration into today’s CMOS technology. Silicon nanoparticles could overcome this problem, as they exhibit bright luminescence and high quantum yield.

The time-resolved photoluminescence (PL) of silicon nanoparticles with different functionalisations such as fluor or dodecene is studied using micro-photoluminescence. We performed PL-measurements at low temperatures to determine the line width of single nanoparticles, which was found to be in the range of several millielectron volts. In time resolved measurements on particle ensembles, this enables us to address a sub-set with a specific diameter by taking into account only a small spectral range of the inhomogeneously broadened Pl spectrum.

We present data of such sub-sets of particles for different laser excitation powers and temperatures and find PL decay characteristics, which can be fitted by bi-exponential or stretched exponential functions. We observe decay-times of up to 300 µs, decreasing below 50 µs for increasing PL energy, an effect, which we attribute to an increasing quantum confinement for smaller nanoparticles. This shows the high technological potential of silicon nanoparticles as their lifetime can be controlled by size.