Characterisation and performance evaluation of amorphous silicon nitride as passivation layer in thin film aSi:H solar cells

Abstract

The fabrication and characterisation of amorphous silicon nitride layer is presented in this paper. The suitability of using it in photovoltaic application has been investigated. It is observed that the band gap of the nitride layers increases with increase in nitrogen content. The experimental results shows that amorphous silicon nitride alloy can be used as passivation layer in devices due to its high optical band gap. On the basis of experimental results, a thin film aSi:H single junction solar cell having aSiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> as passivation layer has been proposed. Further, the behaviour of the proposed structure has been evaluated through simulation using SCAPS1D solar simulator. It is found out that the involvement of amorphous silicon nitride as passivation layer on the top part of the solar cell results in a conversion efficiency of 12.9 % and short circuit current density (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sc</sub> ) of 15.18 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> which are significant values as far as a single junction amorphous silicon thin film solar cell has been considered. Furthermore, a comparison study on solar cell performance parameters of aSi:H solar cell with and without aSiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> passivation layer has been done.