Feasibility of Large-Scale MoS₂ Thin-Film Transistors on a GaN Substrate

Two-dimensional (2D) materials have attracted much attention for their layered structures and diversity in electronic and optical properties. Sapphire and Si/SiO2 were the most common substrates for chemically synthesized MoS2. Here, we demonstrated high-quality large-scale MoS2 film grown by atomic layer deposition (ALD) on an Fe-doped free-standing GaN substrate. In addition, we fabricated excellent performance and highly uniform top-gate FETs based on MoS2, and the average electron mobility of MoS2 FETs was up to 3.54 cm2 V–1 s–1. Furthermore, Al2O3 was introduced to act as a hard mask to prevent direct contact of photoresist and MoS2, which was compatible for the fabrication process and ensured the homogeneity of electrical properties of each FET. Our work paves a new way for chemically synthesized wafer-scale MoS2 film, and it is promising to build large-scale integrated circuits other than FETs on a GaN substrate.