tailieunhanh - Báo cáo hóa học: " Structural Evolution During Formation and Filling of Self-patterned Nanoholes on GaAs (100) Surfaces"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Structural Evolution During Formation and Filling of Self-patterned Nanoholes on GaAs (100) Surfaces | Nanoscale Res Lett 2008 3 530-533 DOI s11671-008-9194-5 NANO EXPRESS Structural Evolution During Formation and Filling of Self-patterned Nanoholes on GaAs 100 Surfaces K. A. Sablon Zh. M. Wang G. J. Salamo Lin Zhou David J. Smith Received 13 October 2008 Accepted 17 October 2008 Published online 4 November 2008 to the authors 2008 Abstract Nanohole formation on an AlAs GaAs superlattice gives insight to both the drilling effect of Ga droplets on AlAs as compared to GaAs and the hole-filling process. The shape and depth of the nanoholes formed on GaAs 100 substrates has been studied by the cross-section transmission electron microscopy. The Ga droplets drill through the AlAs layer at a much slower rate than through GaAs due to differences in activation energy. Refill of the nanohole results in elongated GaAs mounds along the 01-1 direction. As a result of capillarity-induced diffusion GaAs favors growth inside the nanoholes which provides the possibility to fabricate GaAs and AlAs nanostructures. Keywords Atomic force microscopy Transmission electron microscopy Molecular beam epitaxy Over the past decade there has been much emphasis directed toward semiconductor nanostructures 1-4 . One area of epitaxial growth that has attracted attention is that of droplet epitaxy for lattice-matched systems 5 6 . High-temperature droplet epitaxy is a versatile technique with the right growth conditions an intriguing range of nanostructures such as nanoholes double ring-like structures K. A. Sablon H Zh. M. Wang G. J. Salamo Institute of Nanoscale Science and Engineering University of Arkansas Fayetteville AR 72701 USA e-mail ksablon@ L. Zhou D. J. Smith Department of Physics Arizona State University Tempe AZ 85287 USA and quantum dot QD molecules can be obtained 7-12 . Among the many nanostructures fabricated by this method one interesting structure is the nanohole formed on GaAs 100 substrates. Many types of top-down patterning processes have been investigated as