Twist angle between two-dimensional (2D) layers is a critical parameter that determines their interfacial properties, such as moiré excitons and interfacial ferroelectricity. To achieve better control over these properties for fundamental studies and various applications, there have been considerable efforts to manipulate the twist angle. However, due to mechanical limitations and the inevitable formation of incommensurate regions, there remains a challenge in perfectly aligning the crystalline orientation. Here, we report a thermally induced atomic reconstruction of randomly stacked transition metal dichalcogenides (TMDs) multilayers into fully commensurate (FC) heterostructures with zero-twist-angle by encapsulation annealing, regardless of twist angles of as-stacked samples and lattice mismatches. We also demonstrate the selective formation of R- and H-type FC phases with a seamless lateral junction using chemical-vapor-deposited TMDs. The resulting FC phases exhibit strong photoluminescence (PL) enhancement of the interlayer excitons even at room temperature due to their commensurate structure with aligned momentum coordinates. Our work not only shows a way to fabricate zero-twisted 2D bilayers with R and H-type configurations, but also provides a platform for studying their unexplored properties.

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