|
|
| Identifier |
000346154 |
| Title |
Φασματοσκοπία μεμονωμένων πιεζοηλεκτρικών κβαντικών τελειών InAs |
| Alternative Title |
Single piezoelectric InAs quantum dot spectroscopy |
|
Author
|
Ξενογιάννη, Χριστίνα Δ
|
| Abstract |
Single quantum dot spectroscopy is a very useful tool for the study of the QD optical properties. In the recent years research studies have been oriented towards quantum dots grown on polar directions, for example (N11). These heterostructures are strained, which induces strong piezoelectric fields along the growth axis. These fields drastically alter the optical and electrical properties of the QDs. The current project consists of a study of several samples of InAs QDs grown on GaAs(211)B substrates. The QDs were grown by MBE according to the Stranski-Krastanow method, under various growth conditions (temperature, growth rate, growth duration). The samples were structurally characterized using atomic force microscopy (AFM). One of the samples has been selected for optical characterization using the μ-PL method, where single quantum dot emmition spectra have been gathered. In order to isolate the quantum dots, an Al/Cr shadow mask with circular apertures of a few hundreds of nm was fabricated on the surface of the sample. The excitation source used was a cw He-Cd laser emitting at 325nm. The experiments were performed in a liquid He cryostat, at various temperatures ranging between 5 and 80K. The PL emission was detected with a nitrogen-cooled CCD detector. The spectra are dominated by two peaks, the one originated from the exciton and the other from the biexciton emission. The biexciton emission peak appears on the higher energy side of the exciton emission peak, which leads to the conclusion that the biexciton binding energy is negative. The study of the exciton and biexciton binding energies was completed with the construction of a theoretical model consistent with our experimental results
|
| Language |
Greek |
| Subject |
InAs quantum dots |
|
Piezoelectric quantum dots |
|
Single quantum dot spectroscopy |
|
Κβαντικές τελείες InAs |
|
Πιεζοηλεκτρικές κβαντικές τελείες |
|
Φασματοσκοπία μεμονωμένων κβαντικών τελειών |
|
μ-PL |
| Issue date |
2008-07-01 |
| Collection
|
School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Post-graduate theses
|
|
|
Type of Work--Post-graduate theses
|
| Views |
339 |
Φασματοσκοπία μεμονωμένων πιεζοηλεκτρικών κβαντικών τελειών InAs
