Organically capped silicon nanocrystals

Comparing different surfaces, a “model” SiNC is that terminated with hydrogen (H-SiNC) as hydrogen termination influences the physical properties of the silicon core the least. H-SiNCs provide full spectral tunability [212], following the quantum confinement model well (see Section 16.1.1). However, the Si-H bond on the highly curved surface of an SiNC is much weaker than that on a planar Si, being oxidatively unstable and very sensitive to water [31,41,59,191]. Halogenated, for example, chlorine-terminated surfaces, on the other hand, exhibit only weak photoluminescence (PL) in addition to being unstable in ambient air [64]. Therefore, hydrogenated and halogenated SiNCs are regarded as reactive platforms or sometimes convenient study models under controlled atmosphere [64,212], whereas oxide-covered and organically terminated SiNCs are stable entities, with deeper understanding of physical properties reached in the former, but much wider versatility in the latter. Naturally, other types of attachment, such as Si-S linkage [221], have also been studied.