Deposition of Microcrystalline Silicon Thin Film Solar Cells in a Single Chamber System: Completely High Pressure Technique

In this article, we firstly present a study of each layer of the microcrystalline silicon (μc-Si:H ) thin film solar cells prepared in a single chamber by very high frequency-plasma enhanced chemical vapor deposition (VHF-PECVD). The boron-doped microcrystalline silicon (μc-Si:H) films, the intrinsic μc-Si:H films and n-type a-Si films were all deposited at high deposition pressure (1.5 to 2.5Torr). And each layer of the solar cells was deposited at the same electrode distance. The electrical, structural and optical properties of the films were investigated. The dark conductivity as high as 2.75S/cm of ptype μc-Si:H prepared has been achieved at a deposition rate of 1.75Å/s for 25nm thin film. Intrinsic μc-Si:H films with low defect densities were deposited. Through controlling boron and phosphors contamination the single junction μc-Si:H solar cell with 7.62% conversion efficiency (1.0cm2) has been fabricated in a single chamber by VHF-PECVD. Through the optimization of bottom solar cells thickness and application of ZnO/Al back reflector, 10.59% high initial conversion efficiency of micromorph tandem solar cell (1.027cm2) , which bottom solar cell was deposited in a single chamber, with an open circuit voltage of 1.3864V has been fabricated. Micromorph module with 91.5cm2 effective area also shows 9.53% high initial conversion efficiency.