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Single-layered semiconducting crystals for making LEDs energy harvesting

Published online 16 August 2015

Scientists create monolayer semiconductors with many potential applications in electronics.  

Biplab Das

Researchers from Saudi Arabia and Taiwan have synthesized a novel form of semiconducting crystals that could potentially be used to make monolayer light-emitting diodes and energy-harvesting devices1.

Lain-Jong Li and his colleagues from King Abdullah University of Science and Technology (KAUST), Saudi Arabia, and Taiwan-based National Chiao Tung University, used a two-step process to create the two-dimensional semiconductors. 

First, they layered tungsten selenide on a sapphire substrate. They then laterally deposited molybdenum sulfide crystals which surrounded the tungsten selenide crystals, forming a seamless monolayer of heterojunction semiconductors.    

Using scanning Kelvin probe microscopy and other analytical techniques, the scientists found distinct potential and strain differences across the junction of tungsten and molybdenum regions in the semiconducting materials. On applying a tiny threshold voltage, the semiconductors exhibited good rectification character, suggesting good electrical properties.

“Such semiconducting materials are promising for fabricating future flexible, lightweight and low-power consumption electronic devices,” says Li. To scale up the production of such materials, the scientists are developing a prototype cold-wall vapour phase deposition system, he adds.  


  1. Li, M.-Y. et al. Epitaxial growth of a monolayer WSe2-MoS2 lateral p-n junction with an atomically sharp interface. Science (2015).