Extended Data Fig. 10: Confined heterobilayer growth of TMDs (MoS₂/WSe₂) and their characterization.

a–c, Raman mapping of the E¹_2g peak on the MoS₂/WSe₂ heterobilayer at each trench shows that ML-MoS₂ is uniformly filled up (~94%) on top of ML-WSe₂ at the wafer-scale (a). For the MoS₂ layer of the heterobilayer, E¹_2g (384.9 cm⁻¹) and A¹_g (403.1 cm⁻¹) peaks appeared in the Raman spectra (b). As shown in the representative photoluminescence spectra (c), two peaks associated with direct gaps of MoS₂ and WSe₂ were detected, confirming the ML-MoS₂ formation. A slight shift of the peak from the original direct gap occurs due to a well-known interlayer exciton coupling³³. d,e, The high crystalline quality of the MoS₂ was further confirmed by ideal XPS spectra observed in narrow-scan data of Mo (3d_3/2 and 3d_5/2; d) and S (2p_1/2 and 2p_3/2; e), which showed no signs of defects or atomic mixing related Mo⁶⁺ peak at ~236 eV³⁴.