Study of silicon quantum dot p-n or p-i-n junction devices on c-Si substrate

The tandem stack of cells is one of the promising approaches for using a full solar spectrum and improving solar cell performance. By restricting the dimensions of silicon to less than Bohr radius of bulk crystalline silicon (~5 nm), quantum confinement causes its effective bandgap to increase. Therefore silicon quantum dot superlattice can be a good candidate for realizing all silicon tandem solar cells. In this work, silicon quantum dot heteroface and p-i-n homojunction devices on crystalline silicon wafers have been fabricated to understand the electrical properties of these junctions. The conduction mechanisms were determined by analyzing the temperature dependence of the current-voltage characteristics. We have experimentally investigated the material properties of silicon (Si) quantum dot (Si QD) superlattices and fabricated the device as a first step towards silicon based tandem cells. This study indicates the silicon quantum dots can be a good candidate for all-silicon tandem solar cells.