Carrier dynamics of mullti-stacked quantum dots (MSQDs) have been studied by means of time-integrated and time-resolved photoluminescence (PL). The MSQD with different spacer thickness of 10, 15, 20 and 30 nm were grown by molecular beam epitaxy. Time-integrated PL exhibit red shift as spacer thickness increases. The red shift originated from the vertical coupling relaxes the strain in the MSQDs, leading to a decrease in the PL peak energy. From time-resolved PL, the MSQD with spacer thickness increased reveals the shorter lifetime of PL peak among samples studies. We attribute the maximum of lifetime to a better vertical alignment. We report on a measurement of the rise and decay of luminescence intensity in the MSQDs excited at 1.54 eV (808 nm) and 3.09 eV (404 nm). The results show a slow rise time of electrons from the L to the £F valley for high photoexcitation energies. The decay in luminescence is longest with photoexcitation at 3.09 eV, we demonstrate the importance of the penetration depth and carriers tunneling. In addition, the MSQDs strongly depends of on the carrier injection. The rise times decrease with increasing excitation density. The properties are characteristic features of Auger processes.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0811106-001222 |
| Date | 11 August 2006 |
| Creators | Lu, Shu-kai |
| Contributors | Tai-Fa Young, Der-Jun Jang, I-Min Jiang, Li-Wei Tu, Meng-En Lee |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0811106-001222 |
| Rights | campus_withheld, Copyright information available at source archive |
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