Development of MoS 2 /SiO 2 /p-Si heterojunctions with an interfacial SiO 2 layer tuned to an appropriate thickness by CVD

Appropriate control of the interfacial SiO 2 thickness is required for the practical application of chemical vapor deposition (CVD)-based molybdenum disulfide (MoS 2 )/Si devices. This study demonstrates the direct growth of MoS 2 /SiO 2 /p-Si heterojunction, in which the SiO 2 layer functions as an active interfacial layer, using a CVD process with a MoO 3 precursor and p-Si substrates with a native oxide layer. Uniform monolayer MoS 2 films were confirmed by optical microscopy, Raman spectroscopy, and photoluminescence measurements. X-ray photoelectron spectroscopy revealed that the interfacial SiO 2 thickness after MoS 2 synthesis was limited to 2.0 nm, which is suitable for maintaining carrier tunneling and enabling carrier transport. Ultraviolet photoelectron spectroscopy further clarified the work function and band alignment at the MoS 2 /SiO 2 /p-Si interface, indicating favorable energy band bending across the heterojunction.