Probing molecular packing at engineered interfaces in organic field effect transistor and its correlation with charge carrier mobility.
Surface engineering of SiO2 dielectric using different self-assembled monolayer (SAM) has been carried out, and its effect on the molecular packing and growth behavior of copper phthalocyanine (CuPc) has been studied. A correlation between the growth behavior and performance of organic field effect transistors is examined. Depth profiling using positron annihilation and X-ray reflectivity techniques has been employed to characterize the interface between CuPc and the modified and/or unmodified dielectric. We observe the presence of structural defects or disorder due to disorientation of CuPc molecules on the unmodified dielectric and ordered arrangement on the modified dielectrics, consistent with the high charge carrier mobility in organic field effect transistors in the latter. The study also highlights the sensitivity of these techniques to the packing of CuPc molecules on SiO2 modified using different SAMs. Our study also signifies the sensitivity and utility of these two techniques in the characterization of buried interfaces in organic devices.
Priya
P
Maheshwari
Saurabh
S
Mukherjee
Debarati
D
Bhattacharya
Shashwati
S
Sen
Raj Bahadur
RB
Tokas
⊥The Institute of Scientific Research, Osaka University, Osaka, Ibaraki, Japan.
Yoshihide
Y
Honda
Saibal
S
Basu
Narayanan
N
Padma
Pradeep Kumar
PK
Pujari
field effect mobility; interface molecular packing; organic semiconductors; positron annihilation spectroscopy; self-assembled monolayer