In order to reduce the parasitic ab

In order to reduce the parasitic absorption of intrinsic amorphous silicon films, the thickness is controlled at about 6 nm, which is the thinest thickness that can maintain good passivation performance. The thickness of p-a-si film in the window layer requires 10 nm. At this time, the thickness of the whole amorphous silicon film reaches 16 nm, the band gap is only 1.7~1.8eV, and it has strong intrinsic absorption to the short-wave region of the spectrum. In order to reduce the short wave absorption of SHJ solar cells, wide-band gap emitter materials can be used, such as a-sicx :H and a-siox :H instead of a-si :H. In this experiment, p-a-sicx was used to replace p-a-si film, and p-a-sicx with wide-band gap was obtained through a series of film optimization, with higher transmittance at short wave. The influence of CH4 flow rate on film transmittance was studied. As shown in figure 3.1 (a), the transmittance of p-a-sicx film gradually increased with the increase of CH4 content. By measuring the band gap, it is found in figure 3.1 (b) that when the CH4 content increases from 0 to 20 SCCM, the band gap increases from 1.75 eV to 2.1 eV, which is consistent with the transmittance results. P-a-sicx with a band gap of 2 eV was applied in SHJ solar cell as the emitter, and the EQE response of p-a-si as the emitter layer was compared. As shown in FIG. 3.2 (a) and (b), when p-a-sic is used to replace p-a-si as the emitter, parasitic absorption is significantly reduced by FDTD simulation. The experimental results show that the EQE value of the battery in the short-wave range of 300~600nm is significantly higher than that of the battery when p-a-si is used as the emitter.