|A Layer of MoS2 between Two Graphene Sheets / dt.co.kr|
Professor Woo Jong Yu of the School of Electronic and Electrical Engineering at SKKU and the Institute for Basic Science (IBS) Center for Integrated Nanostructure Physics’ joint research team announced on November 9 that they had developed the world’s thinnest semiconductor, ten times thinner than the previous semiconductors. Silicon semiconductors use a p-n junction, which is a double junction that consists of semiconductor materials with different electric properties and that absorbs light, creating optical devices that generate energy. P-n junction, however, cannot be thinner than 14 nanometers (nm) because it is difficult to produce delicate optical devices with two-dimensional materials. Graphene, a carbon nanomaterial that is the basic structure of carbon materials, is considered the “new wonder material” because of its outstanding electrical and chemical characteristics, but it was hard use in semiconductor devices since it has no band gap (difference in energy between the top and bottom bands in semiconductors). The research team overcame this limit by placing a layer of two-dimensional material with no band gap, called molybdenum disulfide (MoS2), between two graphene sheets, resulting in a 13 nm photodetector. The photocurrent, an electric current, between the two materials is very high, and does not need conventional p-n junction to be generated. This technological advancement solves the excessive power consumption and heating problems of silicon semiconductors. Moreover, Professor Yu says, “The device will be used to produce high efficiency photoelectric devices, which can be utilized in wearable devices and Internet of Things (IOT).” This research was published in Nature Communications on November 9.
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