- Title
- Wavelength-modulation spectroscopy for the evaluation of the photoresponse of solar cells
- Creator
- Mandanirina, Nambinintsoa Roméoh Hasinjatovo
- Subject
- Gallium arsenide semiconductors
- Subject
- Solar cells
- Subject
- Modulation spectroscopy
- Date Issued
- 2016
- Date
- 2016
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10948/7244
- Identifier
- vital:21312
- Description
- This study describes the development of a wavelength-modulation spectroscopy technique for the evaluation of solar cell devices. In particular, the technique is used to investigate the sub-bandgap response associated with the incorporation of GaSb quantum rings into the active region of a conventional GaAs p-i-n solar cell. These GaSb/GaAs quantum ring solar cells are a class of third generation cells, with the potential to exceed the Shockley-Queisser efficiency limit of single junction devices. Wavelength-modulation spectroscopy (WMS) techniques involve the modulation of the wavelength of a pseudo-monochromatic light source, with the resulting variation in the measured photocurrent then being a measure of the differential optical response of the solar cell. Although the conventional photocurrent spectrum of a solar cell is a good measure of the optical response characteristics, the differential technique gives supplemental detail related to the absorption spectrum. In addition to the basic WMS setup, we also developed an in situ flux correction module to ensure that a constant excitation intensity is maintained during the wavelength modulation. The excitation source inherently has a spectral dependence that leads to an undesirable contribution to the photocurrent signal. The operation of the flux corrected WMS setup has been demonstrated by photocurrent and photo-capacitance response measurements to obtain the differential quantum efficiency and charging characteristics of the quantum ring solar cells.
- Format
- ix, 62, v leaves: color illustrations
- Format
- Publisher
- Nelson Mandela Metropolitan University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela Metropolitan University
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