In this thesis the strain properties of two InAs/GaAs quantum dot intermediate band solar cell materials have been explored. Both samples were thin films grown on a (100) GaAs substrate. The quantum dot material was InAs, and the bulk material was GaAs. One sample had AlAs-cap, while the other had GaAs-cap. Geometrical phase analysis was used to study the strain. A higher degree of strain was found in the AlAs-capped sample. Negative strain was observed in directly above and below the quantum dots in both samples. A stacking fault in a quantum dot in the AlAs-capped sample was found to relax all the strain. Analysis of the chemical composition of the AlAs-capped sample was performed using HAADF-STEM and multislice analysis. This analysis found an average indium concentration inside the quantum dots of 25% +- 10%, with peaks up to 50%.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:ntnu-13655 |
| Date | January 2011 |
| Creators | Nord, Magnus Kristofer |
| Publisher | Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, Institutt for fysikk |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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