Next to Si-based solar cells, devices based on chalcogenide thin films such as Cu(In,Ga)(S,Se)2 (CIGS) are at the forefront in thin film solar cell technology. Present Si and thin film photovoltaic (PV) technologies have already achieved power conversion efficiencies in excess of 20 %. Full industrialization of these technologies has already been achieved, with more than 100 GWp of solar modules being installed every year. In order to further advance the industrialization of the technology, integration of the cells in construction buildings would be desirable, called building integrated photovoltaics (BIPV). One possible application for solar cells would be in the large areas of windows and glass facades of modern buildings, but for this application the solar cells would need to be at least partially transparent to visible light.
One possibility to achieve transparent solar cells is to combine organic solar cells that only absorb the infra-red part of the spectrum with ultra-high band gap inorganic solar cells that will only absorb the ultraviolet (UV) part of the spectrum.
This master thesis topic consists of the fabrication and characterization of ultra-high band gap chalcogenide absorber layers that can be used as UV solar cells.
Absorber layers consisting of ZnS and ZnSe thin films have a band gap in the 3 eV range and are fully transparent to visible light. Such layers will be fabricated using a cheap and fast two-step selenization approach consisting in evaporation of a metal layer followed by a selenization process at high temperatures. The fabricated layers will then be characterized using optical, physical and electrical measurement techniques.
Optical measurement to be performed will consist in transmission and reflectance measurements, deducing the band gap and transparency of the layers. Physical measurements to be performed will consist in profilometry and scanning electron microscopy measurements, combined with energy dispersive X-ray spectroscopy in order to determine the composition of the layer. Electrical measurements to be performed will consist in resistivity measurements.
The different characterizations will be linked to the growth of the absorber in order to optimize the absorber quality for solar cell applications.
Finally, solar cell structures will be fabricated with the optimized absorber layers and characterized.
Type of project: Internship; Thesis; Combination of internship and thesis
Duration: minimum 6 months
Required degree: Master of Engineering Technology; Master of Science; Master of Engineering Science
Required background: Energy; Materials Engineering; Physics
Imec allowance will be provided