Influence of Li+ doping on the optical properties of PbS

We investigate the influence of Li+ in the optical properties of PbS thin films. PbS and PbS:Li doped films were prepared by chemical bath deposition. Optical studies using the first derivative absorption spectra reveals the multiple exciton generation process associated to the excitonic transitions. The refractive index (n), extinction coefficient (k), and dielectric parameters (ε1 and ε2) were obtained. The analysis of current-temperature measurement in the 12-320 K range shows that the activation energy exhibits lower values with increasing Li+ concentration. The mechanism of current conduction in the films is discussed.