Misaligned monolayers stack up for cheaper electronics

The finding, by researchers at North Carolina State University (NC State) could lower the manufacturing cost for a variety of semiconductor devices such as solar cells, lasers and LEDs.

‘This work demonstrates that by stacking multiple two-dimensional materials in random ways we can create semiconductor junctions that are as functional as those with perfect alignment,’ said Dr Linyou Cao, senior author of a paper on the work and an assistant professor of materials science and engineering at NC State. ‘This could make the manufacture of semiconductor devices an order of magnitude less expensive.’

For most semiconductor electronic or photonic devices to work, they need to have a junction, which is where two semiconductor materials are bound together. In photonic devices like solar cells, lasers and LEDs, the junction is where photons are converted into electrons, or vice versa.

According to NC State, all semiconductor junctions rely on efficient charge transfer between materials, to ensure that current flows smoothly and that a minimum of energy is lost during the transfer. To do that in conventional semiconductor junctions, the crystalline structures of both materials need to match. However, that limits the materials that can be used, because you need to make sure the crystalline structures are compatible. And that limited number of material matches restricts the complexity and range of possible functions for semiconductor junctions.