NO2 Sensors Based on p-6P Heterogametic Induction Growth of Copper Phthalocyanine Thin Films

To realize low concentration NO2 detection at room temperature, copper phthalocyanine (CuPc) organic thin film sensors are fabricated by using a para-hexaphenyl (p-6P) film as the inducing layer. The growing characteristics of the p-6P film at different deposition rates are investigated by atomic force microscopy (AFM). At a low deposition rate, the p-6P film exhibited a horizontal growth mode. The large and thin domains were obtained owing to the sufficient diffusidn time to the island. A CuPc thin film grown on p-6P film showed high order alignments, as observed by the AFM morphology. The CuPc films grew on the optimizing p-6P film by the weak epitaxial technique. The induction effect of the p-6P film to CuPc films was clearly observed by X-ray diffraction (XRD). By comparing the gas response effects of different deposition rates of the p-6P film, a high response intensity and recovery time were achieved at a low deposition rate. Thus, the performances of the CuPc film sensor were significantly improved by the inducing growth of p-6P thin films. The response intensity was twice that of CuPc thin films on silicon dioxide. The recovery time was 3.2 min and the detection concentration for NO2 gas was 1.0 x 10(-1).