Demonstrating A Fully-2D-Material Based Device For Temperature Sensing In Cryogenic Regimes

A technical paper titled “I-V-T Characteristics and Temperature Sensor Performance of a Fully-2D WSe2/MoS2 Heterojunction Diode at Cryogenic Temperatures” was published by researchers at Technische Universität Dresden, Institute of Ion Beam Physics and Materials Research, and National Institute for Materials Science.

Abstract:

“In this work, we demonstrate the usability of a fully-2D-material based device consisting of MoS2/WSe2 heterojunction encapsulated by hBN and contacted by graphene as temperature sensor for linear temperature measurement at cryogenic temperatures. More precisely, temperatures in the range of 10 K up to 300 K were applied to the device while recording the I-V characteristics. In contrast to the classical expectation, the main current flows through the device when it is reversely biased. We ascribe this to a combination of drift-diffusion and band-to-band tunnel-ing, while for very low temperatures (T < 100 K), variable-range hopping or trap-assisted tunneling seems dominant. In case of forward bias, the Schottky contact on the WSe2-anode hinders the charge transport in the voltage range of interest. Additionally, we obtained the activation energy of the saturation current in reverse direction in an Arrhenius diagram. Depending on the bias level, it varies between 100 meV and 300 meV, which may be related to the energy barrier caused by interface traps, generation centers between both semiconducting 2D materials, and the band-to-band tunneling. Furthermore, we investigated the temperature-sensor performance by applying a constant current to the device and measuring the voltage drop at different temperatures. In the range of 40 K up to 300 K, the sensitivity of the sensor is 2 mV/K, which is comparable to Si devices, while the linearity is still lower (R2 0.94). On the other hand, the demonstrated device consists only of 2D materials and is, thus, substrate independent, very thin, and can potentially be fabricated on a fully flexible substrate in a low-cost process.”

Find the technical paper here. Published: June 2023.

C. D. Matthus et al., “I-V-T Characteristics and Temperature Sensor Performance of a Fully-2D WSe2/MoS2 Heterojunction Diode at Cryogenic Temperatures,” in IEEE Journal of the Electron Devices Society, doi: 10.1109/JEDS.2023.3289758.