Strain‐dependent electronic and optical properties are one of the most appealing features of 2D semiconductors, like monolayer (1L) MoS 2 . However, measuring and controlling the homogeneity of strain within the channel is crucial for next‐generation MoS 2 field‐effect transistors (FETs). This article reports a multiscale investigation of backgated FETs fabricated using large‐area 1L MoS 2 flakes grown by liquid‐precursor‐intermediated chemical vapor deposition on SiO 2 /Si substrates. The devices exhibit very attractive properties for ultra‐low power applications, such as an I on / I off > 10 6 and a normally off electrical behavior. The combination of temperature‐dependent analyses of the FET transfer characteristics and nanoscale resolution potential mapping by Kelvin probe force microscopy shows a fully depleted MoS 2 channel at V G = 0 and an effective Schottky barrier Φ B,FB = 0.21 eV at flatband voltage V FB = 17.9 V. An inhomogeneous tensile strain ( ε ) distribution along the channel length is revealed by micro‐Raman and photoluminescence (PL) mapping, with a reduced ε and blue‐shifted PL energy close to the Ni/Au source/drain contacts, suggesting a biaxial compression of 1L MoS 2 induced by metal deposition. The implications of these observations on the effective mass m eff variation along the channel and the current injection from source/drain contacts have been discussed in the perspective of future ultra‐scaled‐devices applications.
Panasci et al. (Sun,) studied this question.