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Study of growth behaviour and microstructure of epitaxially grown self‐assembled Ge quantum dots on nanometer‐scale patterned SiO 2 /Si(001) substrates
Author(s) -
Yoon TaeSik,
Kim HyunMi,
Kim KiBum,
Ryu Du Yeol,
Russell Thomas P.,
Zhao Zuoming,
Liu Jian,
Xie YaHong
Publication year - 2009
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200880589
Subject(s) - quantum dot , materials science , epitaxy , molecular beam epitaxy , nanometre , microstructure , polystyrene , crystallography , substrate (aquarium) , self assembly , nanotechnology , layer (electronics) , composite material , chemistry , polymer , oceanography , geology
The growth behaviour and microstructure of epitaxially grown self‐assembled Ge quantum dots on patterned SiO 2 /Si(001) substrates by molecular beam epitaxy were studied. The hexagonally ordered Si holes with 30 nm thick SiO 2 mask layer having ∼25 nm diameter, ∼40 nm center‐to‐center distance, and density of ∼7 × 10 10 cm –2 , were formed using self‐assembled diblock copolymer, composed of polystyrene and poly(methyl methacrylate) (PS‐ b ‐PMMA). The multiple Ge nuclei are selectively formed along the periphery of the individual Si holes and these nuclei subsequently coalesce forming single dot with an identical size of patterns. The strain of dots is relaxed up to 80%. The lattice planes of some Ge dots are found to be tilted from those of Si substrates. The Ge dots have dislocations at the interface with Si substrate even at the small size of ∼25 nm, resulting from the limited elastic relaxation in the confined patterned structure. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)