A solar cell is a form of photoelectric cell which generates
electrical power by the photovoltaic effect. It is done by
converting the sunlight into electricity directly [I ]-[2].
Photovoltaic industry has grown rapidly in the last several
years. Now, worldwide total installed capacity of photovoltaic
reached at least 178 GW at a cost less than $1/W till date. The
total output power is now greater than 200 billion kWh, which
represents 1 percent demand of worldwide electricity [3]-[4].
So it is strongly desirable to raise the power conversion
efficiency while reducing the costs also. [t is predicted that the
installation rate will grow at a double digit of 16-25 percent
and in the range of 55-57 GW at the end of 20 15.