Organic/inorganic hybrid gate dielectric for high-performance and low-power organic thin-film transistors

High-performance and low-voltage OTFTs have been demonstrated by employing a multilayer dielectric structure where ultrathin PVP (8 nm) is coated on (op of high-κ HfLaO (20 nm). The multilayer dielectric exhibited a low leakage current density of 4.6×10
⁻⁸
A/cm
²
at −3 V while maintaining a high capacitance density of 340 nF/cm
²
. The device with the multilayer dielectric showed superior performance as compared to that of the device with single HfLaO (20 nm) dielectric such as a low threshold voltage (V
T
) of 0.5 V, a low subthreshold slope (SS) of 0.09 V/decade, a high on-off current ratio (I
on
/I
off
) of 5×10
⁵
and a saturation mobility (μ
SAT
) of 0.34 cm
²
V
^×1
s
⁻¹
along with a low operating voltage of −2 V. Due to the enhanced μ
SAT
with the high gate capacitance of the device with multilayer dielectric, we also achieved a high μ
SAT
C
ox
of 114 nF/Vs, thereby leading to superior drain current drivability.