The developement of a femtosecond-time-resolved spectroscopic ellipsometry setup based on a pump-probe technique is described. The characterization of the setup is presented as well as first results of experiments on a c-plane oriented ZnO thin film are shown. Indications for the study of fast charge-carrier dynamics are given.:Introduction 1
1 Theoretical framework 3
1.1 Zinc oxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1 Crystal and band structure . . . . . . . . . . . . . . . . . . . . . 3
1.1.2 Excitons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Dielectric function and electronic transitions . . . . . . . . . . . . . . . . 5
1.2.1 Electronic transitions . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.2 Dielectric function . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Charge carrier dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.1 High excitation effects . . . . . . . . . . . . . . . . . . . . . . . . 8
1.3.2 Charge carrier density-dependent dielectric function model . . . . 9
1.4 Light polarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2 Preliminary experiments 14
2.1 Methods and instrumentation . . . . . . . . . . . . . . . . . . . . . . . . 14
2.2 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3 Experimental challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.4.1 Time-integrated micro-ellipsometry . . . . . . . . . . . . . . . . . 28
2.4.2 Time-resolved ellipsometry . . . . . . . . . . . . . . . . . . . . . . 31
2.4.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3 Conclusive experiments at ELI Beamlines 35
3.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.2 Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3.3 Demonstration of functionality . . . . . . . . . . . . . . . . . . . . . . . . 49
3.3.1 Time-resolved reflectometry . . . . . . . . . . . . . . . . . . . . . 49
3.3.2 Time-resolved ellipsometry . . . . . . . . . . . . . . . . . . . . . . 51
4 Results and discussion 55
4.1 Time-resolved reflectometry . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.2 Time-resolved ellipsometry . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5 Summary and outlook 63
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:34720 |
| Date | 26 July 2019 |
| Creators | Herrfurth, Oliver |
| Contributors | Universität Leipzig |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/acceptedVersion, doc-type:masterThesis, info:eu-repo/semantics/masterThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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