Direct Evaluation of the Quantum Confinement Effect in Single Isolated Ge Nanocrystals.
To address the yet open question regarding the nature of quantum confinement in Ge nanocrystals (Ge NCs) we employed scanning tunneling spectroscopy to monitor the electronic structure of individual isolated Ge NCs as a function of their size. The (single-particle) band gaps extracted from the tunneling spectra increase monotonically with decreasing nanocrystal size, irrespective of the capping ligands, manifesting the effect of quantum confinement. Band-gap widening of ∼1 eV with respect to the bulk value was observed for Ge-NCs 3 nm in diameter. The picture emerging from comparison with theoretical calculations and other experimental results is discussed.
Racah Institute of Physics and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.
Oded
O
Millo
Racah Institute of Physics and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.
Isacc
I
Balberg
Racah Institute of Physics and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.
Doron
D
Azulay
Department of Chemistry, University of Alberta , 11227 Saskatchewan Drive NW, Edmonton, Alberta T6G 2G2, Canada.
Tapas K
TK
Purkait
Department of Chemistry, University of Alberta , 11227 Saskatchewan Drive NW, Edmonton, Alberta T6G 2G2, Canada.
Anindya K
AK
Swarnakar
Department of Chemistry, University of Alberta , 11227 Saskatchewan Drive NW, Edmonton, Alberta T6G 2G2, Canada.
Eric
E
Rivard
Department of Chemistry, University of Alberta , 11227 Saskatchewan Drive NW, Edmonton, Alberta T6G 2G2, Canada.|NRC-National Institute for Nanotechnology , 11421 Saskatchewan Drive NW, Edmonton, Alberta T6G 2M9, Canada.
Jonathan G C
JG
Veinot
D031315:Geranium / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D011789:Quantum Theory
band gap; germanium nanocrystals; quantum confinement; scanning tunneling spectroscopy