Tailored Langmuir-Schaefer Deposition of Few-Layer MoS 2 Nanosheet Films for Electronic Applications.

Few-layer MoS ₂ films stay at the forefront of current research of two-dimensional materials. At present, continuous MoS ₂ films are prepared by chemical vapor deposition (CVD) techniques. Herein, we present a cost-effective fabrication of the large-area spatially uniform films of few-layer MoS ₂ flakes using a modified Langmuir-Schaefer technique. The compression of the liquid-phase exfoliated MoS ₂ flakes on the water subphase was used to form a continuous layer, which was subsequently transferred onto a submerged substrate by removing the subphase. After vacuum annealing, the electrical sheet resistance dropped to a level of 10 kΩ/sq, being highly competitive with that of CVD-deposited MoS ₂ nanosheet films. In addition, a consistent fabrication protocol of the large-area conductive MoS ₂ films was established. The morphology and electrical properties predetermine these films to advanced detecting, sensing, and catalytic applications. A large number of experimental techniques were used to characterize the exfoliated few-layer MoS ₂ flakes and to elucidate the formation of the few-layer MoS ₂ Langmuir film.