The Effect of Rapid Thermal Annealing Towards the Performance of Screen-Printed Si Solar Cell

Abstract

<b>Problem statement:</b> Solar cells are used to capture the photons which generate the energy.&#13; However the efficiency of the cells to turn the amount of photon to electricity needs to be high and so&#13; the cells enhancement is needed. This involved the whole process of the developing of the cells, thus&#13; annealing process is one of the important steps that needs to be optimised.<b> Approach: </b>Only Si solar&#13; cells will be discussed and the processes involved would be metal contact screen printing and metal&#13; paste co-firing. The contacts were first screen printed with Al paste for the rear side and Ag paste for&#13; the front side of the cell. Cells are then fired in the annealing furnace using selected temperature&#13; profile. Few sets of temperature profiles were used in every cycle. <b>Results:</b> After the IV characteristics&#13; were measured such as Voc, Isc, Pmax and fill factor, it shows that when higher annealing temperature&#13; of the profile was used, all the parameter will increase accordingly. However, profile with the highest&#13; annealing temperature will burn the paste as it will decrease the quality of the cell. This is considered&#13; as over heat to the paste. <b>Conclusion: </b>So by optimising the thermal treatment of the annealing process&#13; does improve the performance of the Si solar cell

Study of the effect of local photon annealing on stress in silicon wafers

“…These experimental results primarily indicate a rearrangement of the defect and impurity structure in the wafers after RTA [4][5][6][7][8]. It is safe to conclude that the type of the defects generated by PA or LPA depends primarily on wafer temperature during heat treatment and the presence or absence of a gettering layer affecting defect redistribution in specimen bulk during heat treatment.…”

“…It should be noted that low-energy below-threshold generation of structural defects and complexes in boron doped Cz-Si wafers is a commonly known phenomenon that causes degradation and regeneration of solar cells [20]. One should however remember that the literary data on the origin of the defect-impurity complexes and their possible transformation as a result of RTA are controversial as can be concluded from the short list of works on the topic [4][5][6][7][8].…”

“…On the other hand increasing the diffusion coefficient by almost one order of magnitude allowed implementing deep diffusion of lithium for the synthesis of local charge pump zones in preliminarily synthesized solar cell structures [3]. RTA is widely used for the production of metallic contacts to semiconductors [4]. RTA is also of great interest for researchers as a powerful tool in defect engineering.…”