Silicon Nanophotonics. Basic Principles, Present Status, and Perspectives

0471613 - FZÚ 2017 RIV SG eng M - Monography Chapter
Kůsová, Kateřina - Hapala, Prokop - Jelínek, Pavel - Pelant, Ivan
Band structure of silicon nanocrystals.
Silicon Nanophotonics. Basic Principles, Present Status, and Perspectives. Singapore: Pan Stanford Publishing, 2016 - (Khriachtchev, L.), s. 109-144. ISBN 978-981-4669-76-4
R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GPP204/12/P235; GA ČR(CZ) GA14-02079S
Institutional support: RVO:68378271
Keywords : silicon nanocrystals * band structure * luminescence properties
Subject RIV: BM - Solid Matter Physics ; Magnetism

This chapter puts on a rigorous basis the concept of electronic band structure in semiconductor nanocrystals. We show that, down to a certain limit, this concept has still reasonable meaning, even if the band structure becomes gradually “fuzzy” and minigaps appear within the allowed energy bands with decreasing nanocrystal size. The nanocrystals basically remember the basic features of their “parent” bulk material. In particular, we demonstrate that hydrogen-capped silicon nanocrystals, fully relaxed geometrically and electronically, retain the indirect-bandgap structure down to ≤2 nm. Moreover, we reveal, both computationally and experimentally, that mechanical (tensile) strain applied to the Si nanocrystals via proper surface capping makes these nanocrystals a direct-bandgap material, putting them on a par with standard direct-bandgap semiconductors like GaAs.
Permanent Link: http://hdl.handle.net/11104/0268973