Photosensitivity of top gate C60 based OFETs: Potential applications for high efficiency organic photodetector

• Photoinduced charge transfer across the interface of C60 and parylene.
• Organic photodetector with high responsivity.
• Photoinduced threshold voltage shift.
• Parylene deposition and formation of free radicals.

The comparison of light-induced effects in bottom-gate and top-gate organic field effect transistors (OFETs) provide a clear indication, that the nature of interface between the active layer and the gate dielectric plays a major role in the observed light-induced threshold voltage shift. The nature of interface was also analyzed by electron spin resonance (ESR) experiments, which provides a direct evidence for the creation of free radical species when parylene is deposited on the top of the C60 semiconductor layer. The rate of change of light-induced threshold voltage shift strongly depends on the wavelength and intensity of the incident light, and transverse electric field at the interface. The observed effects provide a strong base for the realization of high efficiency organic photodetectors and optical memory devices. The responsivity of organic photodetector was measured up to 1047 A/W.

Figure optionsDownload as PowerPoint slide