First principles study on the electronic structures of narrow-band spherical quantum dots in direct silicon nanocrystal-insulator systems
<p>We present first principles calculations of the electronic structures of spherically<br /> symmetricquantum dots (QDs) in direct-bandgap silicon nanocrystals which are potentially<br /> confined by an amorphous insulator.We have instructively ascribed the strong conductionvalenc...
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[Yogyakarta] : Fak. MIPA UGM
2007
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| Summary: | <p>We present first principles calculations of the electronic structures of spherically<br />
symmetricquantum dots (QDs) in direct-bandgap silicon nanocrystals which are potentially<br />
confined by an amorphous insulator.We have instructively ascribed the strong conductionvalence<br />
band coupling found in these systems to a strong mixing of the electronic states<br />
which therefore requires a theoretical model to properly account for its effect. Within the<br />
framework of the k.p effective mass method, we have used an 8x8 Kane Hamiltonianfor<br />
realizing the strong admixture in this central force problem and then we have also<br />
considered sets of symmetries associated with these electronic states and their angular<br />
momenta using orthogonal periodic functions (OPFs). To carry out both analytical and<br />
numerical calculations, two Hilbert space tensorial products for defining an appropriate<br />
new Hilbert space have been attempted for the first time in which the symmetric QD<br />
Hamiltonian may be properly defined and manipulated when applying the k.p effective<br />
mass approximation on the spherical QDs. Following the use of Kane bases, the Hilbert<br />
space has been constructed by OPFs. Apparently our results show that the QD electronhole<br />
energies are dependent on the size of QDs as expected.</p> |
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