Doped semiconductors are the most important building elements for modern electronic devices(1). In silicon-based integrated circuits, facile and controllable fabrication and integration of these materials can be realized without introducing a high-resistance interface(2,3). Besides, the emergence of two-dimensional (2D) materials enables the realization of atomically thin integrated circuits(4-9). However, the 2D nature of these materials precludes the use of traditional ion implantation techniques for carrier doping and further hinders device development(10). Here, we demonstrate a solvent based intercalation method to achieve p-type, n-type and degenerately doped semiconductors in the same parent material at the atomically thin limit. In contrast to naturally grown n-type S-vacancy SnS2, Cu intercalated bilayer SnS2 obtained by this technique displays a hole field-effect mobility of similar to 40 cm(2) V(-1)s(-1), and the obtained Co-SnS2 exhibits a metal-like behaviour with sheet resistance comparable to that of few-layer graphene(5). Combining this intercalation technique with lithography, an atomically seamless p-n-metal junction could be further realized with precise size and spatial control, which makes in-plane heterostructures practically applicable for integrated devices and other 2D materials. Therefore, the presented intercalation method can open a new avenue connecting the previously disparate worlds of integrated circuits and atomically thin materials.