Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 56: Non- and Semi-polar Group-III-Nitrides
HL 56.12: Vortrag
Donnerstag, 25. März 2010, 17:00–17:15, H15
Microscopic correlation of real structure and recombination kinetics in semipolar InGaN SQW using spatio-time-resolved cathodoluminescence — •Sebastian Metzner1, Frank Bertram1, Jürgen Christen1, Thomas Wunderer2, Frank Lipski2, Stephan Schwaiger2, and Ferdinand Scholz2 — 1Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg — 2Institute of Optoelectronics, University of Ulm
Highly spatially, spectrally and time-resolved cathodoluminescence microscopy of an InGaN SQW grown on semipolar facets of 3D inverse pyramids formed by MOVPE on hexagonally masked c-plane GaN is presented. The spectra mapping of the SQW exhibits an emission at λ = 400 nm at the center of the inverted pyramids and λ = 530 nm at the hexagonal ridge. For a correlation with the recombination kinetics the same sample area was investigated by time-resolved CL using an electrostatic beam-blanking that switches "on" the electron beam, keeps it "on" for a selected time and turns it "off" extremely fast allowing a transient mapping in single-photon-counting mode. This gives the opportunity to evaluate time-delayed intensity images in order to generate an initial lifetime map by a digital box-car method. So, the high energy emission at the center exhibits initial lifetimes of τ = 200 ps whereas the low energy emission at the ridge developes nearly two orders of magnitude more slowly in time (τ > 13 ns). For different positions along a facet time-delayed spectra were recorded to study the spectral and temporal characteristics of the InGaN SQW observing the impact of localization and polarization fields.