I. Introduction
Transition metal dichalcogenides (TMDs) can be produced as very thin layers and exhibit excellent electrical characteristics suitable for flexible [1], [2] and wearable applications [3], [4], highlighting them as the next-generation semiconductors with great potential. In addition, TMDs have a direct or indirect band depending on the number of layers [5]. Hence, the electrical and optical properties can be controlled. Accordingly, research on various devices, such as optical devices [6], sensors [7], and logic devices [8], is being actively conducted. Several types of TMDs composed of one transition metal element and two chalcogen elements have been reported, such as MoS2 [9], [10], MoSe2 [11], [12], MoTe2 [13], [14], WS2 [15], [16], and WSe2 [17], [18]. Among them, MoSe2 exhibits ambipolar behavior [19]. As a result, both electrons and holes can be injected. Moreover, when applied as an ambipolar circuit, a practical circuit can be implemented with a more straightforward process than before.