Selective Selenium-Substituted Metallic MoTe2 toward Ternary Atomic Layers with Tunable Semiconducting Character

Layered transition metal dichalcogenides (TMDs) belong to a versatile family of two-dimensional materials, having exceptional optical, electronic, physical, and chemical properties. In fact, the intrinsic properties of TMD materials can be facially altered by tuning their chemistry through atomic substitution for various specific applications. Herein, we demonstrate a unique ternary MoSe2x Te(1-x)2 single crystal with a tunable semiconducting behavior via atomic selenium (Se) substitution into metallic molybdenum ditelluride (MoTe2). Combined with synchrotron-based X-ray characterizations, our atomic microscope observation reveals the substitution of tellurium (Te) by Se in the in-plane layer of MoTe2, forming a highly crystalline ternary atomic layer. The temperature dependence of electrical resistance and the angle-resolved photoemission spectroscopy results further confirm the transition from binary metallic MoTe2 to ternary semiconducting MoSe2x Te(1-x)2 with a distinct band structure, in agreement with our first-principles calculations. Meanwhile, the field-effect transistor device fabricated using MoSe2x Te(1-x)2 exhibits excellent gate controllable characteristics with a high ON-OFF ratio of similar to 10(6). The present work highlights a facile substitution strategy to realize tunable functionalities of TMDs and thus will broaden the range of their potential for electronics and other related fields.