The effect of the variation of the concentration factor and interdot distance of InxGa1−xN/GaN QD—IBSC

Power conversion efficiency of conventional solar devices are low because low energy photons cannot excite carriers to the conduction band, therefore do not contribute to the device´s current and high energy photons are not efficiently used due to a poor match to the energy gap. Efficiency of solar cell may be increased in various ways; now-a-days quantum dot intermediate band solar cell (QDIBSC) is most promising approach among them. Introducing intermediate levels into the energy gap of a conventional solar cell; low energy photons can be used to promote charge carriers in a stepwise manner to the conduction band thereby enhancing the current while maintaining a large open-circuit voltage. In this thesis In_XGa_1-XN/InN quantum-dot intermediate band solar cell is calculated by means of solving Schrödinger equation according to the kronig-penney model. On the basis of particular assumptions, the power conversion efficiency is calculated. The results reveal that the In_xGa_1-xN/InN quantum dot intermediate-band solar cell gives much larger power conversion efficiency than that of conventional solar cells and the power conversion efficiency strongly depends on the size of the quantum dot and the inter dot distance.