الفهرس 
Chapter 1 IntroductionOnly 14 pages are availabe for public view
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Abstract
The solar cell efficiency of crystalline silicon is limited by two loss mechanisms: optical losses, and electrical losses. The surface of the silicon wafer reflects more than 35% of incident light. The losses due to carrier recombination in any of the three regions, i.e., emitter, base, or space charge region, greatly affect the short circuit current and open circuit voltage of a cell, lowering its efficiency.
A substantial proportion of modern solar cells are fabricated using p-type silicon wafers, with boron acting as the primary dopant to introduce electrically active charge carriers. However, under illumination, the excess charge carrier lifetime in silicon can diminish, leading to a decrease in solar cell efficiency. This phenomenon, known as light-induced degradation, and can manifest in various forms. A particularly significant form of light-induced degradation arises in boron-doped-silicon, where recombination centers form in a manner linked to both boron and intrinsic oxygen levels
This thesis explores the efficiency of monocrystalline silicon solar cells fabricated based on boron and gallium-doped-silicon wafers. Focusing on the short circuit current a critical parameter of the solar cells’ efficiency, the thesis delves into strategies for enhancing short circuit current by minimizing the optical and the recombination losses, which significantly impact the performance of silicon solar cells. The influence of pyramid size during the texturing process, the thickness of the anti-reflection coating, the boron and phosphorus concentrations at the pn junction on both short circuit current and efficiency are meticulously investigated. Upon achieving optimal efficiency in the case of using boron-doped-silicon, the research proceeds to replace the boron-doped-silicon wafers with gallium-doped-silicon wafers to overcome the light-induced degradation effect and counterparts to assess the impact in efficiency. The results unveiled a significant impact of the texturing process, anti-reflection coating process, and the concentration of impurities at the pn junction on solar cell efficiency. The best efficiency of solar cell is 18.6%, at the value of short circuit current = 8.936 A, were reached with medium-sized, homogeneous pyramids, an anti-reflection coating thickness of 85 nm, and a boron and phosphorus concentration between 〖6.6× 10〗^15,1×〖10〗^20 cm^(-3). After replacing the boron-doped-silicon wafers with gallium-doped-silicon wafers, the parameters of the diffusion process were changed until to obtain the best efficiency. The efficiency of solar cells based on boron and gallium were compared at the same resistivity (0.63 Ω.cm). The solar cells’ efficiency was found to be 17.29% for boron and 17.61% for gallium. The efficiency of 17.61% indicates that gallium is slightly preferred over boron.