双异质诱导层对红荧烯薄膜晶体管性能的影响

Effect of Heterogeneous Inducing Bilayer on the Properties of Rubrene Thin Film Transistors

在二氧化硅衬底上依次真空沉积p-六联苯(p-6P)和酞菁铜(CuPc)构成双异质诱导层,研究了不同衬底温度下双异质诱导层对红荧烯薄膜形貌的影响,以及红荧烯分子在双异质诱导层上的生长过程.分析发现,第二诱导层酞菁铜的局部有序性对红荧烯薄膜的结晶度有直接影响.随着衬底温度的升高,酞菁铜薄膜有序区域面积增大,红荧烯的棒状晶粒也逐渐增大.当酞菁铜和红荧烯的衬底温度均为90℃,红荧烯蒸镀厚度为20 nm时,红荧烯薄膜形成高度有序、内部连接及具有特定方向的棒状晶畴.利用X射线衍射(XRD)和透射电子显微镜(TEM)分析了红荧烯薄膜的晶体结构,发现经过双异质诱导后的红荧烯薄膜转变为多晶形态.另外,红荧烯薄膜晶体管性能也明显提高,开态电流提高了约3个数量级,迁移率提高了30倍,阈值电压降低了20 V.

Inducing growth method was used to improve the crystallinity of rubrene thin films. Heterogeneous inducing bilayers were formed with vacuum deposition p-sexiphenyl（p-6P） and copper phthalocyanine（Cu Pc）on silicon dioxide substrates. The influence of various substrate temperatures on the morphology of rubrene films was investigated. And the growth process of rubrene molecules on heterogeneous inducing bilayer was analyzed. The results showed that the crystalline rubrene films were formed by the partly ordered films of the second Cu Pc inducing layer. The ordered areas of Cu Pc films increased with the substrate temperature. The rod-like crystals of rubrene films also gradually became larger. When the substrate temperatures of Cu Pc and rubrene were both 90 ℃ and the rubrene thickness was 20 nm,the rubrene films formed highly ordered and interconnected rob-like grains with desirable molecular orientation. The rubrene films on heterogeneous bilayers were polycrystalline structure by X-ray diffraction and transmission electron microscope analyses. And the performance of organic thin film transistor devices with the heterogeneous bilayer was obviously improved. The open-state current was improved by about 3 orders of magnitude,the mobility was raised by 30 times,and the threshold voltage was reduced by 20V.