P-type thin films transistors with solution-deposited lead sulfide films as semiconductor

In this paper we demonstrate p-type thin film transistors fabricated with lead sulfide (PbS) as semiconductor deposited by chemical bath deposition methods. Crystallinity and morphology of the resulting PbS films were characterized using X-ray diffraction, atomic force microscopy and scanning electron microscopy. Devices were fabricated using photolithographic processes in a bottom gate configuration with Au as source and drain top contacts. Field effect mobility for as-fabricated devices was ∼ 0.09 cm ² V ^{- 1} s ^{- 1} whereas the mobility for devices annealed at 150 °C/h in forming gas increased up to ∼ 0.14 cm ² V ^{- 1} s ^{- 1}. Besides the thermal annealing, the entire fabrications process was maintained below 100 °C. The electrical performance of the PbS-thin film transistors was studied before and after the 150 °C anneal as well as a function of the PbS active layer thicknesses.