LAUSR

The lead sulfur (PbS) as thin films were deposited on ordinary glass slides, for different deposition times ranging from 30 to 90 min, and for different molar concentrations of lead nitrate (0.01, 0.05, 0.075 and 0.1) mol / l, at ambient temperature of 55 ° C, using thiourea and lead nitrate as source of S2- and Pb2+ ions respectively and TEA as complexing agent. For different deposition times, the films grow preferentially along (200) direction. With increase in deposition time, and at fixed molar concentration the transmittance remained less than 30% and the optical band gap value decreases from 1.8 to 1.6 eV, while the crystallite size increases from 21.9 to 27.8 nm. For various molar concentrations of lead nitrate and with time deposition equal to 60 min, it was observed that the films grow preferentially along (111) or (200) directions, which depend on the molar concentration. Increasing the concentration of lead nitrate leads to decrease the energy gap from 1.58 to 1.37 eV and increase the crystallite sizes from 28.0 to 32.6 nm.