This project developed innovative characterisation (measurement) approaches that allow high quality data to be collected quickly and accurately, thereby providing a way to rapidly improve laser doping.
A (likely fundamental) limitation was identified to the Dopant Contrast Imaging technique that was developed as part of this project. It was found that quantitative imaging of n-doped samples in other words, the determination of the actual concentration of n type dopant atoms from the microscope images is not possible for any of the broad range of microscope settings investigated.
In silicon-based solar cell production, other substances can be added to the silicon to change its electrical properties. This process is called doping.
One way to achieve localised doping is to melt the silicon in a small region, in the presence of the desired dopant element. Laser doping makes it possible to efficiently create local, highly doped regions which are essential for the metal contacts of solar cells. This process could lead to the production of very high efficiency, low cost solar cells.
However, laser doping is a complex process that has proved difficult to understand and master. There is a need for fast, accurate analysis of the properties of laser processed regions that affect the solar cell performance. Such analysis would help speed up the development of optimised doping processes, and promote the widespread implementation of laser doping.
The project developed innovative characterisation (measurement) approaches that allow high quality data to be collected quickly and accurately, thereby providing a way to rapidly improve laser doping.
By combining these techniques with each other and with suitable computational models, and then cross-checking the results, the researchers developed a powerful and highly reliable characterisation toolbox for laser doping.
This toolbox will be applied to the development of two laser processes currently under investigation at the ANU and at the collaborating institution, the Institute for Solar Energy Systems in Hameln, Germany.
Industrial implementation of advanced laser doping processes for solar cell manufacturing will help to achieve more cost effective, high efficiency cell structures such as back contact solar cells.
Since efficiency is a key driver in determining electricity costs from PV, this will contribute to the goal of further lowering the cost of electricity from solar PV systems.