Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 14: Poster I

HL 14.27: Poster

Monday, March 24, 2003, 17:00–19:30, HSZ/P2

Studies of the degradation mechanism in CdZnSSe quantum well laser diodes — •Elena Roventa, Roland Kröger, Matthias Klude, Peter L. Ryder, and Detlef Hommel — Institute of Solid State Physics, University of Bremen, 28359 Bremen

The CdSe/ZnSe based material system is interesting for realisation of optoelectronic devices emitting in the yellow to blue spectral range. We investigated the structure of quantum well (QW) CdZnSSe laser diodes grown by molecular beam epitaxy (MBE) using high resolution transmission electron microscopy (HRTEM).

In conjunction, strain state analysis of the QWs was performed by the DALI software code (Digital Analysis of Lattice Images) and CELFA (Composition Evaluation by the Lattice Fringes Analysis) using the chemically sensitive (002) reflection. Until now the degradation mechanism is not fully understood. Due to the degradation, the Cd content is changing in the active region and the lifetime of these devices is limited.

The investigations focus on a comparison between QW regions before and after degradation. First results show that the mechanism of degradation is connected with a redistribution of Cd in the QW regions which can be quantified by these methods.