Flexible Temperature Sensor with 2D In₂Se₃ Ferroelectric-Semiconductor Field Effect Transistor Exhibiting Record High...

In this study, a In₂Se₃ ferroelectric-semiconductor field-effect transistor is reported for highly sensitive temperature sensing. The high thermal sensitivity of 696%/°C can be achieved by integrating semiconducting behavior and ferroelectricity in In₂Se₃ thin film. By inducing a polarization up state in the ferroelectric-semiconductor by applying gate bias, the carriers within the In₂Se₃ semiconductor are depleted, suppressing channel formation. Under polarization up state, off-currents are very sensitive to temperature variation, following variable range hopping conduction. The drain currents are found to be in proportional to $$ with T₀ of 1.27 × 10¹² K. To achieve variable range hopping transport, defective In₂Se₃ is deposited at low temperatures (240 °C) using spray pyrolysis. Fabricated In₂Se₃ temperature sensor on flexible polyimide substrate can detect a broad range of temperatures (RT to 200 °C) with high stability, exhibiting excellent temperature sensing performance. In addition, the very thin flexible temperature sensor array is demonstrated for large area spatial temperature sensing.