Ultrathin infrared bolometric photodetector based on MoTe2

Abstract

A fast thermal response time is crucial as it directly influences imaging speed and sensitivity. This is particularly important for military applications, such as night vision systems, where precise temperature measurement and high thermal contrast are required. While quantum-type sensors provide rapid detection, their use of hazardous materials and high costs restrict their industrial use. In contrast, bolometers are more cost-effective but have slower response times and face difficulties maintaining absorption rates as thickness decreases. Our study introduces an innovative approach featuring a simple design and an ultra-thin bolometer with over twice the thinness and an impressive absorption efficiency, achieved using materials with high absorption coefficients like TiN and Fabry-Perot resonance. The proposed structure includes a thermoresistive sensing layer (MoTe2-2H, 11 nm), a leakage current blocking layer (HfO2, 10 nm), and infrared absorption layers (TiN, 10 nm). We measured the temperature coefficient of resistance (TCR) of the suspended MoTe2, with a TCR of -0.1 %K-1, which shows feasibility as a sensor. Additionally, we executed the photoresponse of the suspended MoTe2/HfO2/TiN, which needs to be additional fine tuning of the thickness due to leakage current. Our research aims to broaden the application of high-speed sensors based on 2D materials, addressing critical industry needs.