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- Title
Characterization of Band Gaps of Silicon Quantum Dots Synthesized by Etching Silicon Nanopowder with Aqueous Hydrofluoric Acid and Nitric Acid.
- Authors
Thu-Huong Le; Hyun-Dam Jeong
- Abstract
Silicon quantum dots (Si QDs) were synthesized by etching silicon nanopowder with aqueous hydrofluoric acid (HF) and nitric acid (HNO3). Then, the hydride-terminated Si QDs (H-Si QDs) were functionalized by 1-octadecene (ODE). By only controlling the etching time, the maximum luminescence peak of octadecylterminated Si QDs (ODE-Si QDs) was tuned from 404 nm to 507 nm. The average optical gap was increased from 2.60 eV (ODE-Si QDs-5 min) for 5 min of etching to 3.20 eV (ODE-Si QDs-15 min) for 15 min of etching, and to 3.40 eV (ODE-Si QDs-30 min) for 30 min of etching. The electron affinities (EA), ionization potentials (IP), and quasi-particle gap (εqpgap) of the Si QDs were determined by cyclic voltammetry (CV). The quasi-particle gaps obtained from the CV were in good agreement with the average optical gap values from UV-vis absorption. In the case of the ODE-Si QDs-30 min sample, the difference between the quasi-particle gap and the average optical gap gives the electron-hole Coulombic interaction energy. The additional electronic levels of the ODE-Si QDs-30 min and ODE-Si QDs-15 min samples determined by the CV results are interpreted to have originated from the Si=O bond terminating Si QD.
- Subjects
SILICON research; QUANTUM dots; HYDROFLUORIC acid; NITRIC acid; LUMINESCENCE
- Publication
Bulletin of the Korean Chemical Society, 2014, Vol 35, Issue 5, p1523
- ISSN
0253-2964
- Publication type
Article
- DOI
10.5012/bkcs.2014.35.5.1523