Improving Solar Cells: The Role of Phosphorus Doping

Scientists are making big strides in solar cell technology using cadmium telluride (CdTe). One key focus is enhancing the performance of these cells by adding tiny amounts of phosphorus (P) and selenium (Se). They've used advanced microscopes, like Kelvin probe force microscopy (KPFM) and scanning spreading resistance microscopy (SSRM), to study the structure of these solar cells at a very small scale. KPFM helps see how the electrical potential is distributed across the cell. SSRM, on the other hand, shows where the doping happens and how much charge is there. By combining these techniques, researchers found that uneven doping causes problems. The cell's electrical potential is not uniform, which isn't good for its performance. By adding the right amount of phosphorus, they could fix these issues. Low levels of P-doping reduced the uneven potential drop and made the transition between n-type and p-type regions shallower. High levels of P-doping made the potential more even and balanced the doping at the interface. This study shows that understanding the tiny details of how these solar cells are structured is crucial. It also points to ways to make them even more efficient by dealing with the uneven doping and potential issues.