Edge contacts offer significant potential for scaling down 2D transistors due to their minimal contact resistance and reduced contact length. However, their intricate fabrication complicates reproducible large-scale production and evaluation of electrical properties, particularly for p-type channels. Here, the wafer-scale production of p-type nanosheet transistors with pure edge contacts by leveraging the alloying-mediated phase engineering of 2D MoTe_​2 is demonstrated. The relative 1T’-phase stability of W_​xMo_​1-xTe_​2 facilitates the one-pot growth of lateral polymorphic junctions by combining the 2H-single-crystalline MoTe_​2 channels with W_​xMo_​1-xTe_​2 edge contacts. These edge-contact transistors exhibit improved carrier transfer, which is attributed to the impurity-free contact interface and suppressed metal-induced gap states. Consequently, their electrical performance is both exceptional and reproducible, compared with that of transistors fabricated using two-step metallization. Furthermore, irrespective of contact length scaling (8–15 nm), the contact resistivity remains consistently low (≈5.9 × 10^​-7 Ω cm^​2) owing to edge-confined transport, providing a promising ultra-scaled contact scheme for Ångström-node 2D integrated circuits.