Xue Junming

Optimization of n/i and i/p buffer layers in n-i-p hydrogenated microcrystalline silicon solar cells ∗

Hydrogenated microcrystalline silicon (μc-Si:H) intrinsic films and solar cells with n–i–p configuration were prepared by plasma enhanced chemical vapor deposition (PECVD). The influence of n/i and i/p buffer layers on the μc-Si:H cell performance was studied in detail. The experimental results demonstrated that the efficiency is much improved when there is a higher crystallinity at n/i interface and an optimized a-Si:H buffer layer at i/p interface. By combining the above methods, the performance of μc-Si:H single-junction and a-Si:H/μc-Si:H tandem solar cells has been significantly improved.

Stability of thin films of microcrystalline silicon under light soaking

Silicon thin films with different crystalline ratio(Xc) have been deposited by varying silane content(SC) of reactive gases in the RF-PECVD process. The effects of silane content on performance of the materials and the relationship between microstructure and opto-electronic properties were studied by means of Raman measurements, photoconductivity (σph), and dark conductivity (σd), followed by the measurements of light absorption coefficient (α), the product of quantum efficiency, mobility and lifetime (ημτ), before, during and after light soaking, respectively. The results indicate that the microcrystalline silicon near the transition region is suitable to prepare microcrystalline silicon of device grade, and that the amorphous region of the material is responsible to the light induced degradation.