Stability of singly hydrated silanone on silicon quantum dot surfaces: density functional simulations.
A key to understanding the optical characteristics of silicon quantum dots is the role of surface bonded species that introduce states to the band-gap. In particular, oxygen bonded in a silanone configuration is thought to be a source of shifts in emission during oxidation. We report the results of density-functional calculations examining the properties of such surface structures. We find single hydration of a simple, neutral silanone molecule leads to a barrierless conversion into a di-hydroxyl structure, and that similar processes are weakly activated on larger systems. However, we show that charging has a significant impact upon stability, with the attachment of an electron greatly increasing the barrier for converting silanone to di-hydroxyl termination. The relatively stable, negatively-charged silanone structures are predicted to lead to large red-shifts in the onset of optical absorption.
Eyre
R J
RJ
School of Natural Sciences, Newcastle University, Newcastle Upon Tyne, UK. r.j.eyre@ncl.ac.uk
Goss
J P
JP
MacLeod
R M
RM
Briddon
P R
PR
D003198:Computer Simulation; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D045663:Quantum Dots; D012825:Silicon / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D017655:Silicon Compounds; C532122:silanone; D014867:Water; D012825:Silicon