Influence of excitation frequency and electrode separation on the growth of microcrystalline silicon films and their application in single junction microcrystalline solar cell

摘要

Abstract In this paper we present the role of plasma excitation frequency and electsrode separation on the growth of microcrystalline silicon thin films at two different hydrogen dilutions of silane and different power densities. We optimized the process conditions to develop device quality microcrystalline material. Optoelectronic and structural properties of the developed material have been correlated with the solar cell properties. Growth rate ~7 Å/s has been achieved using plasma excitation frequency of 27.12 MHz at 15 mm electrode separation. We have noticed the positive effects after reducing the electrode separation in higher frequency (27.12 MHz). Optimized microcrystalline film of activation energy 0.55 eV and grain size of 14.61 nm has been developed and is applied to fabricate single junction microcrystalline solar cell. Solar cell with initial cell efficiency of 7.75% with short circuit current density of 24.98 mA/cm2 and open circuit voltage of 0.47 V and fill factor of 0.66 has been achieved.