Development of III-V multi-junction solar cells on Ge substrates

Recently a solar cell, one of the oldest photonic devices, draws lots of attention as an alternative method to generate clean electricity. This is mainly due to the concern about global warming, not to its economic availability. In fact the electricity cost generated by Si solar cell, typically ranged from 25 to 35 cents/kWh, is still far expensive compared to the that produce by fossil fuel. One of the reasons is the Si law material is still expensive and the efficiency of the cell is limited to 23 %, in the case of single crystal solar cell. Efforts reducing the electricity cost and achieving the grid parity have been making by increasing the efficiency using back side contact structure or developing of low material consumption structure, says thin film solar cell.