Seminar featuring Ghulam Dastgeer, Sejong University
Two-dimensional layered materials have earned considerable importance in condensed matter physics, especially to construct van der Waals heterojunctions, spintronic and quantum devices. Conventionally, the heterostructures such diodes are composed of n-type and p-type semiconductors and each region transport opposite charges in nature. Foremost, we fabricated a unique tungsten disulfide (WS2)/Black phosphorus (BP) van der waals heterojunction p-n diode which is manipulating the gate dependent static ratification, effect of temperature on its efficiency and photovoltaic effect. Moreover, along with electrical transport in Two-dimensional (2D) materials, we also studied the spin transport induced by electric current, especially in TMDs. In TMDs like WS2 and WSe2, there is a large spin orbit interaction compared to Silicon and graphene, this feature may prove that TMDs are more efficient for the fabrication of spintronic devices. Even the spin transport in this van der Waals TMDs material may be tuned by electrostatic doping with gate biasing. In n-type WS2, the spin transport of the electrons is controlled by applying a back-gate voltage. The spin signal is recorded at various values of gate voltage, the maximum variation in RISHE is recorded at a positive gate voltage +40V. The spin transport of electrons through WS2 sheets is also observed at different temperatures up to 4.2K. The observation of ISHE in TMDs material is interesting and it will be fruitful to fabricate the fast and low power fast spintronic devices to read, write and store the information.
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