High Temperature Performance of MoS2 Thin Film Transistors

Monday, 6 October 2014: 15:50
Expo Center, 1st Floor, Universal 4 (Moon Palace Resort)
M. Shur, S. Rumyantsev (Rensselaer Polytechnic Institute), R. Samnakay, C. Jiang (University of California Riverside, Riverside, California), P. Goli, and A. Balandin (University of California Riverside, Riverside, California 92521 USA)
We report on the characteristics of long channel (1 to 2 micron MoS2 thin film transistors) measured in the temperature range from 25 oC to 200 oC. Using the long channel allowed us minimizing the effect of the contact resistance for a more accurate extraction of the effective field effect mobility in the channel. The extracted field effect mobility, see Fig.1, (varying from 5 to 7 cm2/V-s in different samples) was only a very weak function of temperature.  The on-to-off ratio was ~ 104 at room temperature decreasing to 103 at 220 oC. The devices had the threshold voltage varying from 80 V to 40 V when temperature increased from 25 oC to 220 oC, see Fig. 2. A very large subthreshold slope of nearly 11 V corresponded to the density of states in the energy gap of approximately 3x1013 cm-2 or approximately 3 x1012 1/(eVcm2) at the band edge. The low frequency noise measurements in the range from 1 Hz to 100 Hz revealed 1/f noise with no recombination-generation bulges. The density of traps extracted from the noise data using the McWhorter model was close to that extracted from the temperature measurement. Our results show that MoS2 TFTs can compete with a-Si TFTs and a-Si sensors for high temperature applications.