LAUSR

The facile synthesis of high-quality lead sulfide (PbS) thin films is of great significance for PbS-based infrared detectors and photovoltaic application. PbS thin films still need to be greatly improved in crystallization to meet the requirement in performance of the detectors. Rapid thermal treatment is reported to be capable of rapidly improving the crystallization. Thus in this work PbS thin films are firstly synthesized on p-Si(100) substrates in an alkaline chemical bath, and are then subjected to a 20 min rapid thermal treatment. The impact of rapid thermal treatment temperature (Trtt) is in particular studied on the microstructure and near-infrared absorption of the films. The rapid improvement in crystallization of the films caused by the rapid thermal treatment is also proposed in mechanism. The finding that PbS crystallizes in face-centered cubic structure before the thermal treatment shows the formation of well crystallized PbS in the alkaline chemical bath. The Pb2+ strongly coordinating with triethanolamine molecules is critical for the formation of PbS. PbS thin films tend to be compact in structure, and to increase and then decrease in particle size with increase in Trtt. The red and blue shifts in near-infrared absorption edge of the films with increase in Trtt are reasonably explained by the change in tensile stress. The transfer of energy in the excited quantum-optical process results in the rapid improvement in crystallization of the films.