Development of optimized n-mu c-Si:H-a-Si:H bilayer and its application for improving the performance of single junction a-Si solar cells

摘要

Hydrogenated microcrystalline silicon (mu c-Si:H) films play different types of roles in the fabrication of single and multi-junction amorphous silicon (a-Si)(center dot) solar cells and also act as an active layer in microcrystalline cells which forms the bottom cell of micromorph solar cells. The detailed study of doped microcrystalline layers have not been done properly and there is uncertainty about the role of n-microcrystalline layer on the performance of single junction a-Si solar cells (Poissant et al., 2003). In this paper we have reported the results of deposition of n-type hydrogenated microcrystalline silicon (n-mu c-Si:H) layers with different deposition parameters. The deposition has been done by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique at 13.56 MHz frequency. The detailed characterization of the films include the following: (1) electrical properties by activation energy, dark and photo conductivity, (2) optical properties like band gap and E-04 (3) structural studies which include crystalline fraction by Raman spectroscopy and grain size by X-ray diffraction and AFM, FE-SEM, TEM studies. The interpreted results are also presented.