Evaporation and deposition of alkyl-capped silicon nanocrystals in ultrahigh vacuum.
Nanocrystals are under active investigation because of their interesting size-dependent properties and potential applications. Silicon nanocrystals have been studied for possible uses in optoelectronics, and may be relevant to the understanding of natural processes such as lightning strikes. Gas-phase methods can be used to prepare nanocrystals, and mass spectrometric techniques have been used to analyse Au and CdSe clusters. However, it is difficult to study nanocrystals by such methods unless they are synthesized in the gas phase. In particular, pre-prepared nanocrystals are generally difficult to sublime without decomposition. Here we report the observation that films of alkyl-capped silicon nanocrystals evaporate upon heating in ultrahigh vacuum at 200 degrees C, and the vapour of intact nanocrystals can be collected on a variety of solid substrates. This effect may be useful for the controlled preparation of new quantum-confined silicon structures and could facilitate their mass spectroscopic study and size-selection.
Chao
Yimin
Y
Siller
Lidija
L
Krishnamurthy
Satheesh
S
Coxon
Paul R
PR
Bangert
Ursel
U
Gass
Mhairi
M
Kjeldgaard
Lisbeth
L
Patole
Samson N
SN
Lie
Lars H
LH
O'Farrell
Norah
N
Alsop
Thomas A
TA
Houlton
Andrew
A
Horrocks
Benjamin R
BR
D000478:Alkylation; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties; D014618:Vacuum
D046911:Macromolecular Substances; D012825:Silicon