Advanced silicon wafer preparation (WP3)

WP3 focused on the development of high-quality wafers by assessing electrical and optical requirements for high-efficiency IBC solar cells. The electrical requirements were evaluated in terms of bulk lifetime and uniform wafer resistivity. The optical requirements were evaluated by analysing the light-management scheme of different texturing combinations: flat, random pyramids and modulated surface texturing.

WP3 reached all the project key indicators. The target for production of high-quality wafers were demonstrated by high lifetime and resistivity measurements from wafers tests. We observed that lifetime strongly improved after applying thermal treatments. Optical goals were achieved by using modulated surface texturing scheme together with rear side texturing. Such light-management scheme exhibited not only low reflectance losses but also promising passivation quality for application on IBC devices.

WP3 investigated novel technologies for production of high-quality wafers thus demonstrating that high-efficiency IBC solar cells are achieved from the n-type mono-wafers from an European provider (Norwegian Crystals). Additionally, WP3 produced scientific knowledge for the use of different light trapping schemes on IBC devices including advanced nano-texturing techniques.

Lessons learnt
During the project development, I learnt that all limiting factors for technology development can be anticipated by using advanced computational tools: from material limitations, stability, layers development and patterning design. All these schemes could include light-management and electrical analysis. With this information all threshold indicators can be set in advance and therefore to accelerate the technological development for a successful and realistic results.