Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 48: Poster 2

HL 48.14: Poster

Donnerstag, 26. März 2009, 15:00–17:30, P2

Optical spectroscopy of Ga(N,As,P)/GaP MQW structures — •Christian Karcher, Andreas Schneider, Bernardette Kunert, Kerstin Volz, Wolfgang Stolz, and Wolfram Heimbrodt — Dept. Physics and Material Sciences Center, Philipps-University of Marburg, Germany

Pseudomorphically grown multiple-quantum-well heterostructures of the dilute nitride Ga(NAsP)/(Ga,B)P material system have been studied by means of modulation-, photoluminescence- (PL) and PL excitation - spectroscopy. It is a promising system to achieve integrated optoelectronic devices on Si substrates. By applying hydrostatic pressure upon the samples we are able to determine the offsets of the direct Ga(N,As,P)-bandgap with regard to the indirect bandgap of the GaP-barrier. The obtained results yield additional knowledge about the band structure of the quantum wells, which is essential for achieving room-temperature lasing in the near future. Furthermore, we perform spatially-resolved Raman- and PL-measurements on a sub-μm-level to gain insight into the potential fluctuations caused by the varying composition within the quaternary QWs. By observing significant features such as the Ga-N vibration mode as well as the excitonic PL it is possible to map the mean distribution of Nitrogen and Phosphorous within the sample, which helps to identify statistical effects such as formation of N-clusters within the crystal.