Effect of chemical polish etching and post annealing on the performance of silicon heterojunction solar cells

Amorphous/crystalline silicon heterostructure solar cells have been fabricated by hot wire chemical vapor deposition (HWCVD) on textured p-type substrates. The influence of chemical polish (CP) etching and the post annealing process on the solar cell performance have been studied. The CP treatment leads to a reduction of stress in the i-layer by the slight rounding of the pyramid peaks, therefore improving the deposition coverage and the contact by each layer, which is beneficial for the performance of the solar cells. An optimized etching time of 10–15 s has been obtained. A post annealing process leads to a considerably improved open voltage (Voc), filled factor (FF), and conversion efficiency (η) by restructuring the deposited film and reducing the series resistance. An efficiency of 15.14% is achieved that represents the highest result reported in China for an amorphous/crystalline heterostructure solar cells based on the textured p-type substrates.