Optical Confinement Effect for below 5 µm Thin Film Poly-Si Solar Cell on Glass Substrate

Abstract

The optical confinement effect of a thin film poly-Si solar cell on a glass substrate fabricated by plasma chemical vapor deposition (CVD) at low temperature has been investigated for a cell thickness of less than 5 µ m. The structure of the cell is glass/back reflector/ n-i-p poly-Si/ITO/Ag grid. The cell with a thickness of 3.5 µ m demonstrated an intrinsic efficiency of 9.8%, as independently confirmed by Japan Quality Assurance. The cell is well characterized by the structure of naturally surface texture and enhanced absorption with a back reflector (STAR). The optical confinement effect of the cell with STAR structure explains both the excellent high short circuit current density of above 27 mA/cm 2 for the 4.7 µ m thick cell and the markedly high quantum efficiency at long wavelength as determined through PC1D analysis.