JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, cilt.15, ss.22-24, 2013 (SCI-Expanded)
We have utilized ex-situ spectroscopic ellipsometry and HRTEM to characterize the optical and structural properties of intrinsic a-Si:H thin layer that plays a key role for the improvement of the open circuit voltage in silicon heterojunction solar cells. Intrinsic a-Si:H films were deposited on (100) p-type CZ silicon wafers by using Plasma Enhanced Chemical Vapor Deposition (PECVD) technique at 225 degrees C substrate temperature and deposition time ranges from 15 s to 1800 s. Observed changes in the imaginary part of pseudo dielectric constant, epsilon(2), of c-Si spectrum with two peaks centered in 3.4 eV and 4.2 eV to a-Si:H which has an intermediate spectrum with a soft peak at about 4.2 eV has been analyzed with using effective medium approximation model.