Study and Fabrication of Crystalline Silicon Solar Cell in Bangladesh; Using Thermal Diffusion Technique

The conversion of sunlight into electricity using solar cells system (10-14%) is worthwhile way of producing solar energy. The rapid fall in solar cell prices leads researchers to intensify their research on efficiency improvement of solar cells and to further reduce the costs of the fabrication process. Bangladesh receives strong sunshine throughout the whole year (3.8-6.42 Kw-hr/m2) and it has been found that the average sunshine hours are 6.69, 6.16 and 4.81in winter, summer and monsoon, respectively. Bangladesh has good prospect of converting this sunlight into electricity through solar system, but there is no technology developed to fabricate solar cell locally in our country. To introduce this technology first time in Bangladesh "Bangladesh Atomic Energy Commission" has set up a laboratory to fabricate and research on crystalline silicon solar cell. This paper presents a solar cell fabrication process, in our solar cell fabrication laboratory, starts with a 200μm thick p-type silicon wafer using a diffusion technique with phosphorus oxy-chloride (POCl3) gas source and metallization with screen printer. The resulting solar cell is mono-facial and it is fabricated using phosphorous diffusion and screen printing technique. Initially the efficiency of our fabricated solar cell was very low because it's very sensitive and depends on various parameters. The best achieved efficiency of our fabricated solar cell, using a screen printed and firing through metallization, on 161 cm2 (total area) silicon wafers was about 7.0 %.