Development of High Efficiency Low Cost III-V Solar Cells
| dc.contributor.advisor | Zagozdzon-Wosik, Wanda | |
| dc.contributor.advisor | Freundlich, Alex | |
| dc.contributor.committeeMember | Charlson, Earl J. | |
| dc.contributor.committeeMember | Litvinov, Dmitri | |
| dc.contributor.committeeMember | Ruchhoeft, Paul | |
| dc.contributor.committeeMember | Stokes, Donna W. | |
| dc.creator | Shervin, Kaveh | |
| dc.date.accessioned | 2018-03-13T13:15:12Z | |
| dc.date.available | 2018-03-13T13:15:12Z | |
| dc.date.created | December 2017 | |
| dc.date.issued | 2017-12 | |
| dc.date.submitted | December 2017 | |
| dc.date.updated | 2018-03-13T13:15:13Z | |
| dc.description.abstract | We have investigated the integration of high efficiency solar cells with crystallographically compatible large grain Ge thin films (fabricated on glass) for cost reduction purposes. We have combined defect tolerant III-V dilute nitride (quantum engineered) solar cells and tunnel diode technologies with low cost poly-Ge substrates (developed by Al-Induced Crystallization method). Hence, it was required to allocate our research into three complementary paths, the fabrication of defect tolerant tunnel diodes, implementation of defect tolerant high efficiency quantum structured solar cells and development of low-cost Ge substrates. First, we theoretically and experimentally evaluated the impact of moderate to large dislocation densities on the performance of GaAs tunnel diodes. We have shown for excessive dislocation densities (ND>1×109 cm-2) I-V characteristics undergo a severe degradation. However, for devices with moderate dislocations (about 2×108cm-2), above what has been perceived as acceptable for PV applications, there is even an improvement in term of peak current densities. Next, we studied ultra-thin defect tolerant solar cells compatible with highly defective low-cost substrates. A 1eV quantum engineered design was investigated for elevated absorption capability to compensate device thickness reduction. Dilute nitride III-V materials were used for their ideal bandgap in 4-junction solar cells (lattice matched with Ge), high absorption coefficient and mere valence band offset with GaAs (as an ideal case for quantum engineering). A resonantly coupled multi-quantum well and supperlattice system were theoretically and experimentally studied for the validation of a thermo-tunneling concept. The results suggest a world record Voc beyond the radiative limit (0.4 eV below bandgap). In the last step, we have empirically investigated a low temperature (<400C) Al induced crystallization of amorphous Ge on glass. We were initially able to achieve polycrystalline Ge, mainly oriented towards [111] direction, with grain sizes as large as 200µm. Further, we studied experimental parameters favoring Ge crystallization towards [110] or [100] crystals direction, suitable for solar cells application. The AlOx layer, between Al and Ge layer, have been found a critical parameter facilitating Ge crystallization. The thickness of Al layer has been known as determining parameter in selecting [110] cubic crystals orientation or [100] rhombohedral Ge structure. | |
| dc.description.department | Electrical and Computer Engineering, Department of | |
| dc.format.digitalOrigin | born digital | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/10657/2961 | |
| dc.language.iso | eng | |
| dc.rights | The author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s). | |
| dc.subject | Solar cells | |
| dc.subject | III-V | |
| dc.subject | Dilute nitride | |
| dc.subject | Quantum wells | |
| dc.subject | Ge | |
| dc.subject | Al Induced Crystallization | |
| dc.subject | Thin films | |
| dc.subject | Tunnel Diode | |
| dc.title | Development of High Efficiency Low Cost III-V Solar Cells | |
| dc.type.dcmi | Text | |
| dc.type.genre | Thesis | |
| local.embargo.lift | 2019-12-01 | |
| local.embargo.terms | 2019-12-01 | |
| thesis.degree.college | Cullen College of Engineering | |
| thesis.degree.department | Electrical and Computer Engineering, Department of | |
| thesis.degree.discipline | Electrical Engineering | |
| thesis.degree.grantor | University of Houston | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy |
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