A vertical WSe 2 -MoSe 2 p-n heterostructure with tunable gate rectification.

Here, we report the synthesis of a vertical MoSe 2 /WSe 2 p-n heterostructure using a sputtering-CVD method. Unlike the conventional CVD method, this method produced a continuous MoSe 2 /WSe 2 p-n heterostructure. WSe 2 and MoSe 2 back-gated field effect transistors (FETs) exhibited good gate modulation behavior, and high hole and electron mobilities of ∼2.2 and ∼15.1 cm 2 V -1 s -1 , respectively. The fabricated vertical MoSe 2 /WSe 2 p-n diode showed rectifying I - V behavior with back-gate tunability. The rectification ratio of the diode was increased with increasing gate voltage, and was increased from ∼18 to ∼1600 as the gate bias increased from -40 V to +40 V. This is attributed to the fact that the barrier height between p-WSe 2 and n-MoSe 2 is modulated due to the back-gate bias. The rectification ratio is higher than the previously reported values for the TMDC p-n heterostructure grown by CVD.