| People | Locations | Statistics |
|---|---|---|
| Naji, M. |
| |
| Motta, Antonella |
| |
| Aletan, Dirar |
| |
| Mohamed, Tarek |
| |
| Ertürk, Emre |
| |
| Taccardi, Nicola |
| |
| Kononenko, Denys |
| |
| Petrov, R. H. | Madrid |
|
| Alshaaer, Mazen | Brussels |
|
| Bih, L. |
| |
| Casati, R. |
| |
| Muller, Hermance |
| |
| Kočí, Jan | Prague |
|
| Šuljagić, Marija |
| |
| Kalteremidou, Kalliopi-Artemi | Brussels |
|
| Azam, Siraj |
| |
| Ospanova, Alyiya |
| |
| Blanpain, Bart |
| |
| Ali, M. A. |
| |
| Popa, V. |
| |
| Rančić, M. |
| |
| Ollier, Nadège |
| |
| Azevedo, Nuno Monteiro |
| |
| Landes, Michael |
| |
| Rignanese, Gian-Marco |
|
Iii, J. W. Ager
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (18/18 displayed)
- 2012P-type InGaN across entire composition range
- 2011Mg doped InN and confirmation of free holes in InNcitations
- 2009Electrical and electrothermal transport in InNcitations
- 2007Superheating and supercooling of Ge nanocrystals embedded in SiO 2citations
- 2007Synthesis and optical properties of multiband III-V semiconductor alloyscitations
- 2006Multiband GaNAsP quaternary alloyscitations
- 2005Highly mismatched alloys for intermediate band solar cells
- 2005A chemical approach to 3-D lithographic patterning of Si and Ge nanocrystals
- 2004Oxygen induced band-gap reduction in ZnOxSe1-x alloyscitations
- 2004Group III-nitride alloys as photovoltaic materialscitations
- 2004Effects of pressure on the band structure of highly mismatched Zn1-yMnyOxTe1-x alloyscitations
- 2004Effect of oxygen on the electronic band structure of II-O-VI alloyscitations
- 2004Characterization and manipulation of exposed Ge nanocrystals
- 2003Band-gap bowing effects in BxGa1-xAs alloyscitations
- 2003Narrow bandgap group III-nitride alloyscitations
- 2003Effect of oxygen on the electronic band structure in ZnOxSe1-x alloyscitations
- 2000Effect of nitrogen on the electronic band structure of group III-N-V alloys
- 2000Effect of nitrogen on the band structure of III-N-V alloys
Places of action
| Organizations | Location | People |
|---|
article
Superheating and supercooling of Ge nanocrystals embedded in SiO 2
Abstract
<p>Free-standing nanocrystals exhibit a size-dependant thermodynamic melting point reduction relative to the bulk melting point that is governed by the surface free energy. The presence of an encapsulating matrix, however, alters the interface free energy of nanocrystals and their thermodynamic melting point can either increase or decrease relative to bulk. Furthermore, kinetic contributions can significantly alter the melting behaviours of embedded nanoscale materials. To study the effect of an encapsulating matrix on the melting behaviour of nanocrystals, we performed in situ electron diffraction measurements on Ge nanocrystals embedded in a silicon dioxide matrix. Ge nanocrystals were formed by multi-energy ion implantation into a 500 nm thick silica thin film on a silicon substrate followed by thermal annealing at 900 °C for 1 h. We present results demonstrating that Ge nanocrystals embedded in SiO<sub>2</sub> exhibit a 470 K melting/solidification hysteresis that is approximately symmetric about the bulk melting point. This unique behaviour, which is thought to be impossible for bulk materials, is well described using a classical thermodynamic model that predicts both kinetic supercooling and kinetic superheating. The presence of the silica matrix suppresses surface pre-melting of nanocrystals. Therefore, heterogeneous nucleation of both the liquid phase and the solid phase are required during the heating and cooling cycle. The magnitude of melting hysteresis is governed primarily by the value of the liquid Ge/solid Ge interface free energy, whereas the relative values of the solid Ge/matrix and liquid Ge/matrix interface free energies govern the position of the hysteresis loop in absolute temperature.</p>