Self-biased photovoltaic behavior in van der Waals MoTe2/MoSe2 heterostructures

Abstract The development of p-n diodes formed on thin TMDs is an essential element for facilitating structural miniaturization for optoelectronic applications. So far, 2D materials-based heterostructures involved contact effect and are not entirely related to heterointerfaces. Here, we fabricated and studied the diode rectification of 2D materials-based heterostructures using nanoflakes of p-MoTe 2 and n-MoSe2. Asymmetric contacts are employed (Al/Au/n-MoSe2) and (Pt/Au/p-MoTe2) and achieved a rectification ratio up to 105 to different gate bias. The value of the n is extracted to be (1.5) at zero gate bias. Besides, the device exhibited a responsivity (R) of 430 mAW−1 and external quantum efficiency (EQE) of 98 % at Vbg = 0 V. A built-in potential was detected, which gave rise to open-circuit voltage (VOC) at Ids  = 0 A and short circuit current (I SC) at Vds = 0 V. Furthermore, we also studied that rectifying behavior can be seen in a 2D nanoflake by utilizing asymmetric metal contacts. These findings can have potential applications in upcoming nano-level devices.