The number of applications requiring electronic devices which can resist high temperatures is growing and some, such as turbines and down hole sensing, need devices which can operate at temperatures of more than 200°C.
A team of researchers from the University of California, Riverside and Rensselaer Polytechnic Institute have discovered that molybdenum disulphide (MoS2) may be suitable for thin-film transistors for such extreme temperature applications.
"Our study shows that MoS2 thin film transistors remain functional to temperatures of at least 500K [220°C]," said Professor Alexander Balandin from UC-Riverside. "The transistors also demonstrate stable operation after two months of ageing."
Using standard lithography techniques, Prof Balandin's team built MoS2 transistors on silicon substrates. Some had a few layer, whilst others had up to 18 layers. The relatively thick films were more thermally stable and demonstrated a higher mobility at elevated temperatures, according to Prof Balandin.
By conducting direct current measurement, researchers studied the current-voltage characteristics or functional performance of the fabricated transistor at temperatures from 300K to 500K. They found the device performed differently, but remained functional as temperature increased.
"Mobility and threshold voltage decreased with temperature," Prof Balandin said.
Prof Balandin also noted: "Single layer MoS2 shows a band gap of 1.9eV, larger than that of silicon and gallium arsenide, and this is beneficial for the proposed application."
Author
Graham Pitcher
Source: www.newelectronics.co.uk