Low-temperature admittance spectroscopy for defect characterization in Cu(In,Ga)(S,Se)2 thin-film solar cells

Abstract

We present a methodology to use low-temperature admittance measurements for characterizing defects in thin-film Cu(ln,Ga)(S,Se)2 solar cells, which is a major step towards increased performance. We develop the theory behind admittance spectroscopy at both room and low temperature, focusing on the so-called “loss-map” graphical representation. It allows to distinguish the entangled responses of different loss mechanisms and, combined with SCAPS 1- D simulations, leads to a refined interpretation of experimental admittance measurements. Using this methodology on experimental measurements, we identify the likely presence of an interface defect, and extract its activation energy (EA=0.093eV) and capture cross-section (σ=2.88⋅10−18cm2) .