Comparison the Effect of Size and Inter-dot Spaces in Different Matrix Embedded Silicon Quantum Dots for Photovoltaic Applications

The quantum dot solar cell concept is proposed as a scheme to optimize the efficiency of standard solar cells. The two most significant power loss mechanisms in single band gap solar cells are the inability to absorb photons with energy less than the band gap (transparency loss), and thermalisation of photon energy exceeding the band gap (thermalisation loss). There are several approaches for tackling these losses for instance tandem cell with increasing the number of band gaps or intermediate band solar cell by creating energy level inside the forbidden band of host materials. Quantum confined nanostructures of silicon with barriers of SiO₂ or SiC can potentially fill these criteria and allow designing of tandem cell or intermediate band solar cell with increased absorption given by direct band gap of such quantum confined systems. In this work, the comparison of solar cell is done based on tunneling probability between QDs which depends on dot size, type of matrices (SiO₂ or SiC) and thickness of barrier layer. The simulation results indicate that the chosen of SiC as dielectric matrix for silicon quantum dots could improve the tunneling rates, which provides an efficiency improvement in silicon, based nanostructure solar cells.