Perylene diimide: Synthesis, fabrication and temperature dependent electrical characterization of heterojunction with p-silicon

A novel, n-type, organic semiconductor N-Butyl-N′-(6-hydroxyhexyl)perylene-3,4,9,10-tetracarboxylic acid diimide (N-BuHHPDI) has been successfully synthesized in high yield. The compound has been characterized by atomic force microscopy (AFM) to understand the morphological properties of a new n-type organic semiconducting material. A 120 nm thin film of N-BuHHPDI has been sandwiched between Al and p-Si to form Al/N-BuHHPDI/p-Si device using the vacuum thermal evaporation technique. The electrical properties of sandwich type Al/N-BuHHPDI/p-Si device have been investigated. The current voltage (I-V) characteristics of the device, in dark, have been measured in the temperature range of 300-330 K. At room temperature, the device exhibits rectifying behavior with a rectification ratio of 51.5 at ±6.8 V. The device parameters such as ideality factor, barrier height, series and shunt resistances have been extracted using the conventional I-V characterization method. The effect of temperature on these parameters is also studied. Alternative electrical characterization methods such as Cheung's functions and Norde's techniques have been employed to measure the device parameters for comparison. The conduction mechanisms are investigated through the interface of N-BuHHPDI and p-Si.