Thin EOT MoS2 FET for Efficient Photodetection and Gas Sensing

In this report, we demonstrate photodetection and gas sensing using thin (scaled) effective oxide thickness (EOT) bottom gate molybdenum disulfide (MoS
₂
) field-effect transistors (FETs). The thin EOT enables low voltage operation while the bottom gate architecture eliminates parasitic top gate optical absorption losses during photodetection and provides open top surface area for gas sensing. Electrical characterization of the MoS
₂
FETs shows an on-state mobility of 35 cm
²
/Vs for an operating voltage range of 1 V with excellent electrostatic control. The bottom gate MoS
₂
FETs were employed for photodetection and gas sensing with a low operating voltage range of 0.5 V. High responsivity of 2 A/W, and a photo-amplification ratio of 10
³
were obtained for 532 nm illumination. Sensitivity value of nearly 32% was obtained for N
₂
gas exposure.