A Study On Manipulation Of Electronic And Magnetic Properties Of Few-layered GaTe And Fe₃GeTe₂ Devices

Tremendous chances emerge as the arising of nano-materials,which boost the field of information and energy simultaneously.Two dimensional layered materials(2DLMs),part of nano-materials family,have been studied extensively owing to their unique electronic structures and properties and exhibit potential in data storage and cal-culation as well.It is broadly researched in nano-devices and spintronics and even believed to be the competitive candidate for the next generation of semiconductors.2DLMs could be exfoliated and assembled easily as a result of interlayer van der Waals force.Compared to other fabrication top-down methods,van der Waals heterostructures offer more opportunities for the nano-devices study.Two dimensional semiconductor GaTe was studied thoroughly because of outstanding opto-electronic properties and two dimensional ferromagnet Fe3GeTe2 prevailed recently due to its higher Curie tempera-ture which could be tuned to near temperature.In this study,systematic electrical and magnetic measurements were performed on the devices fabricated based on both above.The main results are listed as follows.GaTe crystals were grown by self-flux method and few-layered GaTe transistors were fabricated with assistance of mechanical exfoliation in glove box and standard fabrication procedure such as electron beam lithography(EBL)and so on.By perform-ing electrical measurement,the mechanism beneath the improvement of device perfor-mance was studied and analyzed.Results indicate that micro-alloying plays an essential role in performance enhancement.The findings provide another approach for lowering contact impedance.GaTe transistors encapsulated in h-BN were fabricated in glove box and electrical transport characterization was carried out.By applying back gate only,metal-insulator transition(MIT)with resistance changes exceeding four orders of magnitude and bipolar behavior were observed in GaTe.Compared to conventional ionic-gating method,side effects are eliminated.The findings demonstrate the potential of GaTe as a platform for correlated system research and provide more reference for device design and fabrication based on it.Fe3GeTe2 crystals were grown by chemical vapor transport method and Fe3GeTe2/Pt bilayer devices were fabricated.By designing the prototype devices and performing the magnetic and electrical characterization,the magnetization switching in Fe3GeTe2 by current induced spin orbit torque(SOT)in Pt were achieved.The findings demonstrate the potential of Fe3GeTe2 for utility of next generation spintronics.