Surface passivation
Example of a lifetime image of a laser processed sample.
The surfaces of solar cells are critical in determining the overall performance of the devices. Typically, surfaces are covered with one or more dielectric materials which serve to optimize both the electronic and optical properties of the surfaces. They may also serve other functions.The interface properties depend on many factors, such as the deposition conditions and resulting detailed properties of the dielectric, the doping profile of the silicon in the near-surface region, the electric charge density in the dielectric, the surface crystal orientation and surface roughness, creating a large matrix of parameters for investigation.
Several dielectric materials are being studied in detail. These include silicon dioxide, silicon nitride, and titanium dioxide. Of particular interest are multilayer stacks in which two or more dielectrics are used to allow more flexibility in optimizing the electronic, optical and other required properties of the surface and interface regions.
We utilize a range of measurement techniques to obtain a good understanding of the material systems we are studying. These include charge carrier lifetime, capacitance-voltage, electron paramagnetic resonance, Kelvin probe, and ellipsometry measurements.
New Projects
New projects include an ARC Linkage project with partners Spark Solar and Centrotherm to study aspects of surface passivation, and an ARC Linkage project with partners Spark Solar and BraggOne to study the application of spray-on films for the hydrogenation of the surface as well as the bulk of silicon wafers.
Publications in this and other research areas
Contacts
In this area we collaborate with the Semiconductors & Solar Cells Group.
