Nanotechnology / Condensed Matter Physics Seminar
September 14 @ 11:00 AM - 12:00 PM - PHYS 242
Title: Electronic and Optoelectronic Transport Properties of Carbon Nanotube/ Organic Semiconductor Devices*
Due to their exceptional electronic and optoelectronics properties, carbon nanotubes (CNTs) thin films are considered to be a promising electronic material for future nanoelectronics device applications. We studied electronic and optoelectronic transport properties of CNT and CNT/Organic semiconductors (OSC) thin film devices. The CNT thin films were used as an electrode material in the organic electronic devices, whereas CNT thin films were used as an active channel material in the optoelectronic devices. In first part of this talk, I will discuss device properties and charge injection mechanisms of organic field effect transistors (OFETs) with CNT aligned array electrodes. I will show that OFETs with CNT electrodes have higher mobility, higher current on-off ratio, and higher cut-off frequency than that of the OFETs with metal electrodes. The improved device performance of the OFETs with CNT electrodes is attributed to a lower charge injection barrier at the CNT/OSC interface. Using low temperature transport measurements, I will show that the barrier height at CNT/OSC interface is lower than that of at metal/OSC interface. In second part of this talk, I will present photoresponse of the CNT and CNT/polymer composite films. Photoresponse of these films is position dependent and the maximum photoresponse occurs at the metal/CNT film interfaces, which is explained by Schottky barrier modulation. The slow time response of photocurrent is explained by diffusion of charge carriers in the nanotube films. Photoresponse of the CNT/polymer composite film can be tuned by changing the weight percentage of CNT into the polymer matrix.