tailieunhanh - Báo cáo hóa học: " In situ Control of Si/Ge Growth on Stripe-Patterned Substrates Using Reflection High-Energy Electron "

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: In situ Control of Si/Ge Growth on Stripe-Patterned Substrates Using Reflection High-Energy Electron | Nanoscale Res Lett 2010 5 1935-1941 DOI s11671-010-9814-8 SPECIAL ISSUE ARTICLE In situ Control of Si Ge Growth on Stripe-Patterned Substrates Using Reflection High-Energy Electron Diffraction and Scanning Tunneling Microscopy B. Sanduijav D. G. Matei G. Springholz Received 9 July 2010 Accepted 17 September 2010 Published online 6 October 2010 The Author s 2010. This article is published with open access at Abstract Si and Ge growth on the stripe-patterned Si 001 substrates is studied using in situ reflection high-energy electron diffraction RHEED and scanning tunneling microscopy STM . During Si buffer growth the evolution of RHEED patterns reveals a rapid change of the stripe morphology from a multifaceted U to a singlefaceted V geometry with 119 sidewall facets. This allows to control the pattern morphology and to stop Si buffer growth once a well-defined stripe geometry is formed. Subsequent Ge growth on V -shaped stripes was performed at two different temperatures of 520 and 600 C. At low temperature of 520 C pronounced sidewall ripples are formed at a critical coverage of monolayers as revealed by the appearance of splitted diffraction streaks in RHEED. At 600 C the ripple onset is shifted toward higher coverages and at monolayers dome islands are formed at the bottom of the stripes. These observations are in excellent agreement with STM images recorded at different Ge coverages. Therefore RHEED is an efficient tool for in situ control of the growth process on stripe-patterned substrate templates. The comparison of the results obtained at different temperature reveals the importance of kinetics on the island formation process on patterned substrates. Keywords Quantum dots Silicon Germanium Molecular beam epitaxy Patterned substrates Reflection B. Sanduijav D. G. Matei G. Springholz Institut fur Halbleiterphysik Johannes Kepler University 4040 Linz Austria e-mail Present Address D. G. Matei University