Fabrication of p-type BaCuSF and n-type In₂O₃:Sn bilayer films and their applications to the back contact of CdS/CdTe solar cells

Abstract

For applications to polycrystalline thin-film tandem solar cells, we studied p-type conductive BaCuSF single layer and p-type BaCuSF and n-type In 2 O 3 :Sn (ITO) bilayer films. The BaCuSF films were prepared by pulsed laser deposition (PLD), and the ITO films were prepared by RF sputtering. The bilayer film showed ohmic current-voltage characteristic. A tunnel junction between these two layers was successfully fabricated, because p-type BaCuSF and n-type ITO layers had sufficiently high carrier concentrations. The BaCuSF/ITO bilayer films were employed as the back electrodes of CdS/CdTe solar cells. A CdTe solar cell with a 20-nm-thick BaCuSF/a 300-nm-thick ITO bilayer back contact showed a high conversion efficiency of 13.9% (V OC = 818 mV, J SC = 25.2 mA/cm 2 , and FF = 0.675), which was higher than that of a CdTe solar cell with a BaCuSF single-layer back contact (11.1%). The efficiency is comparable to that of a CdTe solar cell with a SrCuSeF/ITO bilayer back contact (14.3%).

Back contacts materials used in thin film CdTe solar cells—A review

“…Doping with sodium 196 gave a small improvement in FF raising the PCE to 14.7% (V oc 806 mV, J sc 27.5 mA cm −2 , and FF 66.1%). Substituting sulfur for selenium (BaCuSF), 197 again used with ITO on top (platinum metallization), gave PCE 13.9% (V oc 818 mV, J sc 25.2 mA cm −2 , and FF 67.5%).…”

Gamma-ray irradiation effects on CdTe solar cell dosimeter

“…The CdTe solar cells were fabricated by the method reported in previous papers. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] For evaluation of the γ-ray tolerance, γ-ray irradiation was divided into multiple time-frames. γ irradiations were provided at the 60 Co γ-ray irradiation facility at Institute for Integrated Radiation and Nuclear Science, Kyoto University.…”