"High anisotropic self-assembled multilayered films used simultaneously as dielectric and conducting channel material for field effect transistor application"

Autores: Gabriel Gaal, Maria Luisa Braunger, Varlei Rodrigues, Antonio Riul Jr., Henrique Leonel Gomes.

Instituições: UNICAMP

Autor apresentador: Gabriel Gaal

Resumo: OFETs have historically suffered from the lack of a seamless interface between the dielectric material and the semiconductor. The hard interface present in current OFETs have defects and active electrical impurities which acts as primary source of electrical instabilities and reliability issues and prevented the commercialization of such devices. Here we show a simple approach to fabricate high electrical anisotropic film and apply it in a novel type of organic transistor without material discontinuities between dielectric and channel. Composite thin films were fabricated by self-assembled layer-by-layer (LbL) deposition technique, exploiting the spontaneous physical interactions that allow for the natural combination of various materials in a single coating. Conductive phases formed by rGO nanoplatelets and PEDOT:PSS fibers are dynamically ordered within a semi-insulating (PEI/PAA) polymeric matrix, creating highly anisotropic pathways. The in-plane film conductivity is 5 orders of magnitude higher than the conductivity normal to the multilayered planes, and temperature dependent measurements confirm the strong anisotropic electrical behavior; charge transport is weekly thermal activated (EA = 33.4 meV) along the aligned conductive phases while the charge transport normal to the plane is fitted with variable ranging hopping having an activation energy of 1.0 eV. The LbL films’ high anisotropic electrical conduction is used to fabricate a novel field effect transistor with a seamless dielectric/semiconductor interface. The transistor presents a low power consumption as it operates at the sub voltage regime, and the dielectric part shows a high specific capacitance of 18 µF/cm2. The semiconductor presents an n-type carrier transport having a field effect mobility of 4.0 cm2V-1s-1. Moreover, the transistor threshold voltage is zero, which shows that the entire applied gate field contributes to the modulation of channel current, as expected in trap free devices.

Link do vídeo: https://youtu.be/9aPNQdnRQBI

Link da sala do Meet: https://meet.google.com/kva-hvmf-cvr