عنوان البحث(Papers / Research Title)
Surface and core electronic structure of oxidized silicon nanocrystals
الناشر \ المحرر \ الكاتب (Author / Editor / Publisher)
احمد محمود عبد اللطيف الخفاجي
Citation Information
احمد,محمود,عبد,اللطيف,الخفاجي ,Surface and core electronic structure of oxidized silicon nanocrystals , Time 5/8/2011 1:58:47 PM : كلية العلوم
وصف الابستركت (Abstract)
Ab initio Hartree-Fock method is used to study silicon nanocrystals
الوصف الكامل (Full Abstract)
Ab initio restricted Hartree-Fock method within the framework of large unit cell formalism is used to simulate relatively large silicon nanocrystals between 216 and 1000 atoms that include Bravais and primitive cell multiples. The investigated properties include oxidized surface and core properties. Results revealed that electronic properties converge to some limit as the size of the nanocrystal increases. Increasing the size of the core of a nanocrystal resulted in an increase of energy gap, valance band width, and cohesive energy. The lattice constant of the core and oxidized surface parts show a decreasing trend as the nanocrystal increases in size that converges to 5.28 ?. Surface and core convergence to the same lattice constant reflects good adherence of oxide layer at the surface. The core density of states shows a highly degenerate states that split at the oxygenated (001)-(1×1) surface due to symmetry breaking. The nanocrystal surface shows smaller gap, higher valence and conduction bands when compared to the core part due to oxygen surface atoms and reduced structural symmetry. Nanocrystal geometry proved to have strong influence on all electronic properties including the energy gap.
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