Effect of Reaction Time and Temperature on Chemical, Structural, Optical, and Photoelectrical Properties of PbS Thin Films Chemically Deposited from the Pb(OAc)2–NaOH–TU–TEA Aqueous System
文摘
Lead sulfide (PbS) thin films have been deposited on float glass substrates by the chemical bath deposition technique using a Pb(CH3COO)2–NaOH–(NH2)2CS–N(CH2CH2OH)3 definite aqueous system. The chemical and structural characteristics, as well as the variation of the optical and photoelectrical properties, were studied as functions of reaction time and temperature. For this purpose, the following characterization techniques were employed: x-ray diffraction analysis, x-ray photoelectron spectroscopy, ultraviolet–visible–near infrared spectrophotometry, and dark and light current measurements. Based on the results, it was observed that increase in the reaction temperature increased the deposition rate of the PbS thin film (associated with the cubic crystalline structure); increase of this parameter from 40°C to 70°C (with reaction time of 60 min) led to an increase of the thickness from ∼129 nm to ∼459 nm and the crystallite size (D) from 15.3 nm to 20.2 nm; on the other hand, increase in temperature decreased the energy bandgap (Eg) from 1.66 eV to 0.51 eV and the relative photosensitivity factor (Sph) from 0.468 to 0.032. A similar effect was obtained with increase of the reaction time for given temperature.