Improvements in the device characteristics of random-network single-walled carbon nanotube transistors by using high- κ gate insulators

The authors fabricated random-network single-walled carbon nanotube field-effect transistors (FETs) with high- κ gate insulators. The gate insulator in the FETs was changed from Si O2 to Ba0.4 Sr0.6 Ti0.96 O3 (BST, εs =100), which was fabricated by a sol-gel method. The gate-switching voltage of a FET with a BST insulator is about one-tenth of that of a FET with a Si O2 insulator, and the values of the transconductance and the on/off ratio are 0.18 μS and 105, respectively. In addition, hysteresis in the operation of the FETs was dramatically decreased, probably because of improvements in the surface condition of the insulator.