Prolonged Annealing Improves Hole Transport of Silicon Heterojunction Solar Cells

The Schottky barrier is a fundamental issue when an n-type transparent conductive oxide (TCO) is contacted with p-type hydrogenated amorphous silicon (p-a-Si:H) in silicon heterojunction (SHJ) solar cells. Herein, it is found that the hydrogen (H) atoms in p-a-Si:H diffuse into tungsten-doped indium oxide (IWO) during annealing, which improves the electric properties of both the IWO films and the p-a-Si:H/IWO interface. H diffusion reduces the surface work function of p-a-Si:H, and thus reduces the Schottky barrier between the p-a-Si:H and the IWO. Consequently, it improves the hole transport of SHJ solar cells; i.e., both the fill factor (FF) and power conversion efficiency (PCE) substantially increase. These findings provide a new strategy to optimize the FF of SHJ solar cells.

Automated summary

The diffusion of hydrogen atoms can reduce the Schottky barrier between p-a-Si:H and IWO, thereby improving the hole transport in SHJ solar cells and increasing both the fill factor and power conversion efficiency.