Atomic Layer Deposition of Al 2 O 3 Directly on 2D Materials for High‐Performance Electronics

Due to the lack of surface dangling bonds of 2D materials such as graphene, hexagonal boron nitride, MoS2 etc., deposition of high-kappa dielectrics directly on such 2D materials by atomic layer deposition (ALD) is difficult and a nucleation layer is usually required. Here an ALD approach is developed to deposit high-kappa dielectric layer, e.g., Al2O3, directly on 2D materials without the aid of the nucleation layer or introducing structural damages. In this approach, an individual deposition cycle includes one incremental organometallic pulse and multiple H2O pulses to guarantee the uniform deposition of high-quality high-kappa dielectric layers on graphene, MoS2, and other 2D materials directly. Large-scale top-gated MoS2 field-effect transistors (FETs) with Al2O3 as dielectric layers exhibit excellent performances including high on/off ratio exceeding 10(8) and mobility up to 70 cm(2) V-1 s(-1). The high-quality Al2O3 layer is also integrated into MoS2 based flexible FETs and inverters, and a significant voltage gain of 412 is obtained. This ALD approach also works for other materials like gold with inert surfaces, showing great promise for novel electronics.