High Temperature Performance of MoS2 Thin Film Transistors

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.