optimization of chalcogenide cdte, czts and cztse solar cells performancesusing cd1-xznxs buffer layer

Cadmium zinc sulfide (cd1-xznxs) as a wide-band gap material with x=0.7 was used inthe present work as an alternative buffer material to cds to improve the efficiency ofzno/cd1-xznxs/cdte, zno/cd1-xznxs/czts and zno/cd1-xznxs/cztse thin film solar cells. the photovoltaic parameters such as efficiency, open circuit voltage (voc), short circuit current density (jsc) and the fill factor (ff) have been computed using one-dimensional simulation programs such as solar cell capacitance simulator (scaps v3.3) and analysis of microelectronic and photonic structures (amps-1d). an improvement in conversion efficiency isnoticed compared to the structure with the cds buffer layer. it is found that the efficiencies of cd1-xznxs/cztse and cd1-xznxs/cdteareincreased from 12.61% to 15.35% and from 17.53% to 18.83%, respectively. the simulations were performed for 1 µmthick absorber layers.it is also found that the efficiency rises from 12.53% to 13.23% with cd1-xznxs/czts structure for czts thickness of 2.5 µm. moreover, the quantum efficiency (qe) characteristics display the maximum value of more than 80% in the visible rangeand the structures presented a slight improvement in the short wavelength. the present study shows that the suggested structures with acd1-xznxs buffer layer may improve the efficiency and reduce the amount of cd, which is a toxic element.