Wednesday February 23, 2005
4 PM
PHO 339

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"Nucleation of Defect-free, Monolithic AlSb on Si using Self-Assembled Quantum Dots (Joint ECE/CNN Colloquium)"
Diana Huffaker
University of New Mexico

We discuss our recent demonstration of photopumped III-V lasers on Si. The room temperature lasing spectrum is centered at 2.0 mm. The InGaSb quantum well active region is grown atop a defect-free AlSb bulk material on a Si (001) substrate. The highly mismatched epitaxial growth of AlSb on Si is enabled by a monolithic self-assembled AlSb quantum dot (QD) nucleation layer. During the first few monolayers of AlSb growth on Si (001), highly crystalline QDs form. With continued deposition, the islands coalesce into a planar material with no detectable defects. The quality of the buffers is determined by HR-TEM and HR-XRD. The TEM data indicates a defect free AlSb bulk and highly crystalline interface between the Si and the AlSb. The QD nucleation layer facilitates a completely relaxed AlSb within ~100 ML of deposition according to X-Ray diffraction. We attribute the unique growth mode of AlSb on Si to both the large AlSb/Si lattice mismatch (Dao/ao=13.5%) in combination with the strong AlSb atomic bond. Materials characteristics and initial device measurements will be discussed.

Bio: Professor Diana Huffaker is an Associate Professor of Electrical and Computer Engineering at the University of New Mexico. Her research interests include epitaxy and characterization of strained materials in III/V and III-N systems, physics of nanostructures and coherent processes in QDs. Professor Huffaker has co-authored over 100 refereed journal publications and 2 book chapters, and has reported her work through many invited presentations. She has been awarded the 2002 Compound Semiconductor International Symposium Young Scientist Award and the 2004 Alexander von Humboldt research fellowship.

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