Improvement of a-Si:H/c-Si Heterojunction Solar Cells through higher deposition temperature

In a-Si:H/c-Si heterojunction solar cells, the key factor to the high performance are the a-Si:H/c-Si heterointerface and anti-reflection structure. First, we use the high temperature (250 ℃) to deposit a-Si:H layers to improve the interface passivation due to the films quality is better. By inserting high temperature deposition of intrinsic a-Si:H to be the passivation layer, the open circuit voltage (Voc) is apparently increased. Moreover, we concentrate on the interface treatment of the a-Si:H/c-Si interface. Before depositing the a-Si:H films by PECVD, we use the hydrogen treatment to pre-treat the c-Si surface by a low energy plasma. The hydrogen plasma treatment improve both the open circuit voltage (Voc) and fill factor (F.F.) and thereby increase the conversion efficiency of solar cell due to the good passivation of interface and the increase of build-in potential. Second, the anti-reflection structure is introduced to improve the device performance. We use textured substrate formed by wet chemical etching method. By means of this structure, the short circuit current density (Jsc) can be largely enhanced and the efficiency is improved. Finally, the plasma treatment and BSF structure are used in this textured substrate of HIT solar cell. The conversion efficiency is achieved to 16.38%.