scholarly journals Imaging “Invisible” Dopant Atoms in Semiconductor Nanocrystals

Nano Letters ◽  
2011 ◽  
Vol 11 (12) ◽  
pp. 5553-5557 ◽  
Author(s):  
Aloysius A. Gunawan ◽  
K. Andre Mkhoyan ◽  
Andrew W. Wills ◽  
Malcolm G. Thomas ◽  
David J. Norris
Keyword(s):  
Semiconductor Nanocrystals ◽  
Dopant Atoms

scholarly journals Reversal of the Charge Transfer between Host and Dopant Atoms in Semiconductor Nanocrystals

Nano Letters ◽  
2004 ◽  
Vol 4 (11) ◽  
pp. 2251-2254 ◽  
Author(s):  
Torbjörn Blomquist ◽  
George Kirczenow
Keyword(s):  
Charge Transfer ◽  
Semiconductor Nanocrystals ◽  
Dopant Atoms

scholarly journals Imaging ‘Invisible’ Dopant Atoms in Semiconductor Nanocrystals

2012 ◽  
Vol 18 (S2) ◽  
pp. 298-299
Author(s):  
A.A. Gunawan ◽  
A. Wills ◽  
A. Mkhoyan ◽  
M.G. Thomas ◽  
D.J. Norris
Keyword(s):  
Semiconductor Nanocrystals ◽  
Dopant Atoms

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Effects of dopant concentration on the microstructure of tin- doped indium oxide thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 716-717
Author(s):  
I. A. Rauf
Keyword(s):  
Thin Films ◽  
Indium Oxide ◽  
Ionic Radius ◽  
Free Carrier ◽  
Electron Gun ◽  
Periodic Lattice ◽  
Oxide Thin Films ◽  
Transmission Electron ◽  
The Difference ◽  
Dopant Atoms

To understand the electronic conduction mechanism in Sn-doped indium oxide thin films, it is important to study the effect of dopant atoms on the neighbouring indium oxide lattice. Ideally Sn is a substitutional dopant at random indium sites. The difference in valence (Sn4+ replaces In3+) requires that an extra electron is donated to the lattice and thus contributes to the free carrier density. But since Sn is an adjacent member of the same row in the periodic table, the difference in the ionic radius (In3+: 0.218 nm; Sn4+: 0.205 nm) will introduce a strain in the indium oxide lattice. Free carrier electron waves will no longer see a perfect periodic lattice and will be scattered, resulting in the reduction of free carrier mobility, which will lower the electrical conductivity (an undesirable effect in most applications).One of the main objectives of the present investigation is to understand the effects of the strain (produced by difference in the ionic radius) on the microstructure of the indium oxide lattice when the doping level is increased to give high carrier densities. Sn-doped indium oxide thin films were prepared with four different concentrations: 9, 10, 11 and 12 mol. % of SnO2 in the starting material. All the samples were prepared at an oxygen partial pressure of 0.067 Pa and a substrate temperature of 250°C using an Edwards 306 coating unit with an electron gun attachment for heating the crucible. These deposition conditions have been found to give optimum electrical properties in Sn-doped indium oxide films. A JEOL 2000EX transmission electron microscope was used to investigate the specimen microstructure.

Spins in Semiconductor Nanocrystals

Priroda ◽  
2018 ◽  
pp. 22-31
Author(s):  
A. Rodina ◽  
◽  
D. Yakovlev ◽  
Keyword(s):  
Semiconductor Nanocrystals

scholarly journals Dynamic lattice distortions driven by surface trapping in semiconductor nanocrystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Burak Guzelturk ◽  
Benjamin L. Cotts ◽  
Dipti Jasrasaria ◽  
John P. Philbin ◽  
David A. Hanifi ◽  
...  
Keyword(s):  
Photon Energy ◽  
Semiconductor Nanocrystals ◽  
Atomic Scale ◽  
Atomistic Simulations ◽  
Shell System ◽  
Structural Distortions ◽  
Colloidal Semiconductor Nanocrystals ◽  
Femtosecond Electron Diffraction ◽  
Structural Deformations ◽  
Nonradiative Processes

AbstractNonradiative processes limit optoelectronic functionality of nanocrystals and curb their device performance. Nevertheless, the dynamic structural origins of nonradiative relaxations in such materials are not understood. Here, femtosecond electron diffraction measurements corroborated by atomistic simulations uncover transient lattice deformations accompanying radiationless electronic processes in colloidal semiconductor nanocrystals. Investigation of the excitation energy dependence in a core/shell system shows that hot carriers created by a photon energy considerably larger than the bandgap induce structural distortions at nanocrystal surfaces on few picosecond timescales associated with the localization of trapped holes. On the other hand, carriers created by a photon energy close to the bandgap of the core in the same system result in transient lattice heating that occurs on a much longer 200 picosecond timescale, dominated by an Auger heating mechanism. Elucidation of the structural deformations associated with the surface trapping of hot holes provides atomic-scale insights into the mechanisms deteriorating optoelectronic performance and a pathway towards minimizing these losses in nanocrystal devices.

scholarly journals Understanding Discrete Growth in Semiconductor Nanocrystals: Nanoplatelets and Magic-Sized Clusters

2021 ◽  
Vol 54 (7) ◽  
pp. 1545-1554
Author(s):  
Andrew B. Pun ◽  
Sergio Mazzotti ◽  
Aniket S. Mule ◽  
David J. Norris
Keyword(s):  
Semiconductor Nanocrystals
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