二维六方氮化硼薄膜的制备及光电特性研究

Preparation and photoelectric properties of h-BN two-dimensional film

以六方氮化硼(h-BN)粉末为原料,氩气为携载气体,利用热蒸发沉积法在硅衬底上制备了h-BN二维薄膜。应用原子力显微镜观察了薄膜的表面形貌,发现该方法生长的膜均匀而光滑,其厚度为4 nm,对应十几层的h-BN。利用X射线衍射分析了h-BN薄膜的结构,发现h-BN薄膜主要由(002)晶面排列构成,说明其生长方式为典型的层状生长模式。利用紫外可见光光谱仪测量了其吸收特性,发现该样品在209 nm附近有很强的吸收。最后,研究了h-BN/Si异质结的接触特性和电子输运特性,发现该异质结具有良好的整流特性,在光照下该异质结的光电流显著增大,表明h-BN薄膜具有良好的光电学特性,可用来制备超薄光电子器件。

Two-dimensional material boron nitride(h-BN)has attracted much attention of researchers due to its excellent photoelectric properties.The h-BN two-dimensional film was prepared on silicon substrate by thermal evaporation deposition in the range of 600~900℃ using h-BN powder as the raw material and argon gas as carrier gas.The surface morphology of the deposited h-BN film was observed by atomic force microscopy.The film was found to have a very uniform and smooth surface with the thickness of 4 nm,corresponding to more than ten layers of h-BN.The structure of the h-BN film was analyzed by X-ray diffraction.It was found that the h-BN film mainly consists of(002)crystal layer,indicating that the growth is a typically layered growth mode.The absorption characteristics were measured by an ultraviolet-visible spectrometer.It was found that the sample has a strong absorption near 673 nm.Finally,we studied the contact characteristics and electron transport properties of the h-BN/Si heterojunction,and found that the heterojunction has good rectification characteristics,and that the photocurrent of the heterojunction increases significantly under illumination,indicating that the h-BN film has good optoelectronic properties and can be used to prepare ultrathin optoelectronic devices.