The application of light trapping structures and of InGaAs/GaAs quantum wells and quantum dots to improving the performance of single-junction GaAs solar cells

Repository

The application of light trapping structures and of InGaAs/GaAs quantum wells and quantum dots to improving the performance of single-junction GaAs solar cells

Show simple record

dc.contributor.advisor Yu, Edward T.
dc.creator McPheeters, Claiborne Ott
dc.date.accessioned 2012-07-12T13:51:41Z
dc.date.available 2012-07-12T13:51:41Z
dc.date.created 2012-05
dc.date.issued 2012-07-12
dc.date.submitted May 2012
dc.identifier.uri http://hdl.handle.net/2152/ETD-UT-2012-05-5040
dc.description.abstract High efficiency photovoltaic solar cells are expected to continue to be important for a variety of terrestrial and space power applications. Solar cells made of optically thick materials often cannot meet the cost, efficiency, or physical requirements for specialized applications and, increasingly, for traditional applications. This dissertation investigates improving the performance of single-junction GaAs solar cells by incorporating InGaAs/GaAs quantum wells and quantum dots to increase their spectral response bandwidth, and by incorporating structures that confine light in the devices to improve their absorption of it. InGaAs/GaAs quantum dots-in-wells extend the response of GaAs homojunction devices to wavelengths >1200 nm. Nanoparticles that are randomly deposited on the top of optically thick devices scatter light into waveguide modes of the device structures, increasing their absorption of electromagnetic energy and improving their short-circuit current by up to 16%. Multiply periodic diffractive structures have been optimized using rigorous software algorithms and fabricated on the back sides of thin film quantum dot-in-well solar cells, improving their spectral response at wavelengths 850 nm to 1200 nm, where only the quantum dot-in-well structures absorb light, by factors of up to 10. The improvement results from coupling of diffracted light to waveguide modes of the thin film device structure, and from Fabry-Perot interference effects. Simulations of absorption in these device structures corroborate the measured results and indicate that quantum well solar cells of ~2 µm in thickness, and which are equipped with optimized backside gratings, can achieve 1 Sun Airmass 0 short-circuit current densities of up to ~5 mA/cm2 (15%) greater than GaAs homojunction devices, and of up to >2 mA/cm2 (7%) greater than quantum well devices, with planar back reflectors. A combination of Fabry-Perot interference and diffraction into waveguide modes of the thin devices is shown to dominate the simulated device response spectra. Simulations also demonstrate the importance of low-loss metals for realizing optimal light trapping structures. Such device geometries are promising for reducing the cost of high efficiency solar cells that may be suitable for a variety of traditional and emerging applications.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subject GaAs
dc.subject InAs
dc.subject InGaAs
dc.subject GaInAs
dc.subject Solar cell
dc.subject Photovoltaic
dc.subject Thin film
dc.subject Quantum well
dc.subject Quantum dot
dc.subject Light trapping
dc.subject Waveguide
dc.subject Nanoparticle
dc.subject Diffraction
dc.subject Grating
dc.subject Scattering
dc.title The application of light trapping structures and of InGaAs/GaAs quantum wells and quantum dots to improving the performance of single-junction GaAs solar cells
dc.date.updated 2012-07-12T13:52:02Z
dc.identifier.slug 2152/ETD-UT-2012-05-5040
dc.contributor.committeeMember Alu, Andrea
dc.contributor.committeeMember Bank, Seth R.
dc.contributor.committeeMember Chen, Ray T.
dc.contributor.committeeMember Zhang, John X.
dc.description.department Electrical and Computer Engineering
dc.type.genre thesis
dc.type.material text
thesis.degree.department Electrical and Computer Engineering
thesis.degree.discipline Electrical and Computer Engineering
thesis.degree.grantor University of Texas at Austin
thesis.degree.level Doctoral
thesis.degree.name Doctor of Philosophy

Files in this work

Size: 5.309Mb
Format: application/pdf

This work appears in the following Collection(s)

Show simple record


Advanced Search

Browse

My Account

Statistics

Information