Fabrication And Characterization Of Back Gate Black Phosphorus Field Effect Transistors Based On PET Flexible Substrate

Black Phosphorus is a kind of layered material,which is stacked in the independent atomic layer by the internal fan Edward force,much like bulk graphite.Inside a single layer,each phosphorus atom is ccovalently bonded with three adjacent phosphorus atoms to form a puckered honeycomb structure.The three bonds take up all three valence electrons of phosphorus,so,unlike graphene,monolayer black phosphorus(termed 'phosphorene')is a semiconductor with a predicted direct bandgap of-2 eV at the ? point of the first Brillouin zone.For few-layer phosphorene,interlayer interactions reduce the bandgap for each layer added,and eventually reach-0.3 eV for bulk black phosphorus.Such a band structure provides a much needed gap for the field-effect transistor(FET)application of two-dimensional materials such as graphene,and have excellent transistor performance at room temperature.As a new type of transistor device,BPFET has a great prospect in the application of nano electronic devices.So far,the application of BPFET in flexible electronic equipment is still in the stage of research and development.First by magnetron sputtering on PET flexible substrate(magnetron sputtering)deposition layer thickness of indium tin oxide 110Nm(ITO),and then by atomic layer deposition technology(Atomic layer deposition,ALD)depositing a layer thickness of 70nm Al2O3,as the transistor substrate.Subsequently,a certain number of black phosphorus was prepared by mechanical stripping method and transferred to substrate by PDMS slice.Then by using atomic force microscopy(AFM)respectively on black phosphorus film thickness is 13.5nm,19nm,23nm and 38nm of thickness,three-dimensional map,topography and friction atoms were characterized,and the Raman films of different thickness of black phosphorus by Raman spectroscopy(Raman).Then,the prepared gold(Au)film is attached to both ends of the black phosphorus channel as the source and drain electrode of the transistor,and the transistor is finished.Finally,the electrical characteristics of the transistors fabricated by black phosphorus films with thickness of 38nm are investigated by means of a probe.This qualitative inquiry that black phosphorus of different thickness on the characterization of AFM friction ring will peak as the thickness increases,the friction ring has the tendency of expansion;also the research that the increase in the Raman characterization of features in a certain range with the thickness of the peak shift,continue to increase as the thickness of the red shift has a decreasing tendency.These work provide the basis for choosing suitable phosphorus material as semiconductor channel of transistors.The output characteristics and transfer characteristics of the back gate black phosphorus field-effect transistors based on PET flexible substrate are also investigated.The output characteristics of PET flexible substrate back gate field effect transistor based on black phosphorus showed the characteristics of ohmic contact transistor P doped;on the transfer characteristics of holes in the PET flexible substrate back gate field effect transistor of black phosphorus based on the migration rate of 266.6 cm2V-1s-1,the electron mobility of 3.5 cm2V-1s-1,hole migration the rate is 75 times higher than the electron mobility At the hole end has a switching ratio of more than 8.6 ×103.The experimental results show that the electrical performance of the device exhibits good Schottky diode characteristics and achieves the experimental purpose.This paper based on PET flexible substrate black phosphorus back gate field effect transistor performance and low cost,the research and application of nano transistor for our development,but also helps to flexible electronic devices.