Batch fabrication of MoS2 devices directly on growth substrates by step engineering

Monolayer molybdenum disulfide (MoS2) has emerged as one of the most promising channel materials for next-generation nanoelectronics and optoelectronics owing to its atomic thickness, dangling-bond-free flat surface, and high electrical quality. Currently, high-quality monolayer MoS2 wafers are primarily grown on sapphire substrates incompatible with conventional device fabrication, and thus transfer processes to a suitable substrate are typically required before the device can be processed. Here, we demonstrate the batch production of transfer-free MoS2 top-gate devices directly on sapphire growth substrates via step engineering. By introducing substrate steps on growth substrate sapphire, high-κ dielectric layers with superior quality and uniform can be directly deposited on the epitaxially grown monolayer MoS2. For the substrate with a maximum step density of 100 µm−1, the gate capacitance can reach ∼ 1.87 µF·cm−2, while the interface trap state density (Dit) can be as low as ∼ 7.6 × 1010 cm−2·eV−1. The direct deposition of high-quality dielectric layers on grown monolayer MoS2 enables the batch fabrication of top-gate devices devoid of transfer and thus excellent device yield of > 96