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HL: Fachverband Halbleiterphysik

HL 85: Poster Session II

HL 85.114: Poster

Donnerstag, 17. März 2011, 18:00–21:00, P4

Interpretation of photoluminescence decay at the limits of time-resolution — •Markus Göthlich, Torsten Langer, Uwe Rossow, and Andreas Hangleiter — Institut für Angewandte Physik, Technische Universität Braunschweig

Time-resolved photoluminescence spectroscopy using time-correlated single photon counting is a reliable way to measure carrier lifetimes that are long compared to the temporal resolution of the instruments. But problems arise, when carrier lifetimes become comparable or even shorter than that: A convolution of the real intensity decay I_true(t) and the response function of the instruments h(t) leads to a significant broadening of the resulting experimental intensity transients I_exp.(t)=∫_−∞^th(t−τ)I_true(τ)dτ. This not only affects the lifetime values obtained from the experiment. There is also an influence on the shape of the transients. In this contribution, we discuss different numerical methods of deconvolving h(t) with the aim to reconstruct the “true” decay transients and to improve the over-all time-resolution of the experimental setup. A possible method is based on Fourier transforms, as deconvolution is simple in Fourier space. Other numerical methods solve a set of linear equations: I_{exp., j}=h_ji· I_{true, i}. Both ways are very sensitive to experimentally inevitable noise, making deconvolution a sophisticated task. We test different algorithms by applying them to simulated convolved transients where the true lifetime is known. Furthermore, we demonstrate the application on measured transients of GaInN/GaN quantum well structures.