High performance flexible organic thin film transistors (OTFTs) with octadecyltrichlorsilane/ Al2O3/poly(4-vinylphenol) multilayer insulators.
The incorporation of a thin, atomic layer deposited Al2O3 layer in between a spin-coated poly-4-vinyl phenol (PVP) organic layer and octadecyltrichlorsilane (OTS) in the multilayer gate dielectric for pentacene organic thin film transistors on a n(+)-Si substrate reduced the gate leakage current and thereby significantly enhanced the current on/off ratio up to 2.8 x 10(6). Addition of the OTS monolayer on the UV-treated Al2O3 improved the crystallinity of the pentacene layer, where the OTS/UV-treated Al2O3 surfaces increased their contact angles to 100 degrees. X-ray diffraction (XRD) analysis revealed a more intense (001) crystal reflectance of pentacene deposited on OTS/UV-treated Al2O3 surface than that on OTS/Al2O3 surface. Moreover, the improved pentacene layer contributed to the field effect mobility (0.4 cm2/Vs) and subsequently improved the electrical performances of organic thin film transistor (OTFT) devices. This PVP/UV treated Al2O3/OTS multilayer gate dielectric stack was superior to those of the device with the single PVP gate dielectrics due to the improved crystallinity of pentacene.
Center for Materials and Processes of Self-Assembly, School of Advanced Materials Engineering, Kookmin University, Seoul 136-702, Republic of Korea.
Mohammad Arifur
MA
Rahman
Hyunho
H
Kim
Young Kyu
YK
Lee
Chiyoung
C
Lee
Hosoek
H
Nam
Jang-Sik
JS
Lee
Hoesup
H
Soh
Jong-Kwon
JK
Lee
Eun-Gu
EG
Lee
Jaegab
J
Lee