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Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.43 [2005] >
IJPAP Vol.43(03) [March 2005] >
| Title: | Role of hydrogen and oxygen on the band gap of silicon quantum dots |
| Authors: | Ghoshal, S K
Gupta, Umesh
Gill, Karan Singh |
| Keywords: | Quantum dots
Nanostructure
Confinement
Radiative recombination
Passivation photoluminescence
Pseudo-potential and HOMO-LUMO states |
| Issue Date: | Mar-2005 |
| Publisher: | CSIR |
| IPC Code: | H01L29/76 |
| Abstract: | A computer
simulation using empirical pseudo-potential Hamiltonian has been performed to
examine the variation of the band gap as a function of size and shape of small
silicon (Si) quantum dots. It has been found that the gap decreases with
increasing dot size. Furthermore, the band gap increases as much as 0.13 eV and
0.35 eV on passivating the surface of the dot with hydrogen and oxygen,
respectively. So both quantum confinement and surface passivation determine the
optical and electronic properties of Si quantum dots. Visible luminescence is
probably due to radiative recombination of electrons and holes in the quantum
confined nanostructures. The entire energy spectrum starting from the very low
lying ground state to the very high lying excited states for silicon dots
having 5, 8, 17 and 18 atoms has been investigated. The role of surface states
on the gap energy as well as on the HOMO-LUMO states has also been examined.
The results for the size dependence of the HOMO-LUMO gap and the wave functions
for the bonding-anti-bonding states have been presented. The role of hydrogen
and oxygen passivation on the confinement is also discussed. |
| Page(s): | 188-191 |
| ISSN: | 0975-1041 (Online); 0019-5596 (Print) |
| Source: | IJPAP Vol.43(03) [March 2005]
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