Multifunctional WSe2/MoSe2/WSe2/MoSe2 heterostructures

The use of two-dimensional (2D) materials-based multifunctional electronic devices and sensors has been boosted in recent years. In this paper, we reported the fabrication of multifunctional heterostructures based on 2D molybdenum diselenide (MoSe2) and 2D tungsten diselenide (WSe2) on oxidized and highly-doped silicon substrate. We carried out morphological characterizations using scanning electron microscopy (SEM) and atomic force microscopy (AFM), as well Raman spectroscopy. Thereafter, we studied the electrical characteristics of PN junctions, NPN and PNP junctions, and PNPN heterojunctions, where results demonstrated that WSe2/MoSe2 junctions had diode-like and Schottky-diode-like behaviors, MoSe2/WSe2/MoSe2 and WSe2/MoSe2/WSe2 had bipolar-junction-transistor-like (BJT) behaviors, and WSe2/MoSe2/WSe2/MoSe2 heterojunction showed tunneling effect. The optoelectronic properties of MoSe2/WSe2/MoSe2 and WSe2/MoSe2/WSe2 was carried out and the phototransistors exhibits strong and tunable photodetection properties, with a high photoresponsivity of 6 and 3 AW-1, respectively.