Band gap engineering of amorphous silicon quantum dots for light-emitting diodes

Amorphous silicon quantum dots (a-Si QDs), which show a quantum confinement effect were grown in a silicon nitride film by plasma-enhanced chemical vapor deposition. Red, green, blue, and white photoluminescence were observed from the a-Si QD structures by controlling the dot size. An orange light-emitting diode (LED) was fabricated using a-Si QDs with a mean size of 2.0 nm. The turn-on voltage was less than 5 V. An external quantum efficiency of 2×10−3% was also demonstrated. These results show that a LED using a-Si QDs embedded in the silicon nitride film is superior in terms of electrical and optical properties to other Si-based LEDs.