Preparation And Study On Characterization Of Black Phosphorus

Black phosphorus has attracted broad interest because of their low-dimensional effect, and has become a new kind of two-dimensional(2D) materials. Phosphorus has several allotropes including white phosphorus, red phosphorus and black phosphorus. Black phosphorus is the most thermodynamic stable in them. It is a natural p-type semiconductor in which each layer is vertically stacked by the van der Waals force. The thickness of black phosphorus can be scaled down to the atomic layer scale known as phosphorene. The unique properties in black phosphorus, along with its high carrier mobility, makes it as a promising material in electronic applications.In this article, red phosphorus successfully turned to black phosphorus by mechanical ball milling method and vapor-phase transport method. The influence of process parameters to the synthetic product was analyzed in the process of experiment. X-ray diffraction(XRD), differential scanning calorimeter(DSC), atomic force microscopy(AFM), transmission electron microscopy(TEM), scanning electron microscope(SEM) were used to analysis of black phosphorus synthesized by two methods. Red phosphorus turned to be black phosphorus by high energy ball milling method at the voltage of 110 V for 1.5 h. The method is simple, highly effective, nontoxic, but the obtained black phosphorus has very small size, low crystallinity and purity. To get black phosphorus by chemical vapor phase transfer, furnace with two temperature zones was used and the raw material was put at the hot zone. In the preparation process, hot zone was heated from room temperature(20 oC) to 650 oC within 30 min and then cooled to 545 oC within 7.5 h; The cold zone was heated from room temperature(20 oC) to 550 oC within 30 min, and then cooled to 445 oC within 7.5 h. Black phosphorus were then obtained after cooling to room temperature with the furnace. Black phosphorus prepared by this method has lager size, high crystallinity and purity.A series of phosphorene samples were prepared by liquid exfoliation. Different chemical reagents, ultrasonic power, ultrasonic time and centrifugal rate were chosen to prepare phosphorene systematically. It has been found that DMF is the best chemical reagents, and the rate of 6000r/min is the best para-meters. Besides, the best ultrasonic power and time are 400 W and 4 h, respectively. In addition, the UV-vis absorption spectrμms and other common spectrμms characterization methods proved the successful preparation of low-layer phosphorene. Then, phosphorene ink was successfully synthesised, and a film of 100 nm height was printed by it.In addition, electrical performance of the low-layer black phosphorus was measured using a business-transmission microscope scanning probe system pole in the transmission electron microscopy(TEM). It is found that that the low-layer black phosphorus has a good electrical conductivity in vacuμm atmosphere, and its resistance was 3.175 MΩ. A field effect transistor based on low-layer black phosphorus was made and measured the responsivity to light. It could fast respond to white light, the response factor(R) was 11 m A/W, and responsivity was within 50 ms. The results that the field effect transistor based on low-layer black phosphorus has a good performance. Black phosphorus has a promising to become a new semiconductor material.