Deposition of p-type Al doped PbS thin films for heterostructure solar cell device using feasible nebulizer spray pyrolysis technique

Abstract

Doping of metal atoms with PbS thin films can make significant influence on the structural and electron transport properties which makes it suitable for photovoltaic and other device applications. The objective of the present work is to study the structural, morphological, optical and electrical properties of PbS:Al thin films as a function of different Al doping percentage. PbS and Al doped PbS thin films were deposited using Nebulizer Spray Pyrolysis (NSP) on soda lime glass substrates by varying Al doping level from 0 wt% to 8 wt%. Polycrystalline nature with face centered cubic crystal structure was noticed for all the prepared films from XRD pattern. The orientation along (200) plane was observed for all the prepared films. From AFM analysis, the observed surface roughness values were considerably decreased on increasing the Al doping concentration. The calculated optical band gap values exhibits increasing trend and shifted from 1.54 eV to 1.66 eV on increasing Al doping concentration. The electrical resistivity value of the PbS:Al thin films were reduced from 3.08 × 103 to 1.63 × 103 Ωcm with raise in Al doping level. The solar cell efficiency for FTO/n-CdS/p-PbS:Al structure constructed from 6% of Al doped PbS film was about 0.44%.