First principles computer model showing the effect of p-layer thickness and front contact barrier height on the performance of a-Si:H p-i-n solar cells

The performance of a-Si:H p-i-n solar cells with different p-layer thicknesses, front contact barrier heights, and front contact/p-layer hole transport mechanisms were modeled. The authors examined how p-layer material and contact quality influenced the results obtained, and they also explored the role that tunneling of holes across the barrier near the front contact can play in determining cell performance. It was found that, for active p-layer cells with the optimistic p-layer activation energy of 0.27 eV, cell performance is maximum for a p-layer thickness of about 100 Å. However, this maximum depends on the quality of the p-layer. Surprisingly, it was found that, for front contact barrier height values less than some critical value, cell performance, in the absence of tunneling, depends on the front contact barrier height regardless of the thickness or quality of the p-layer