UV-C LEDs and lasers: low-voltage light sources for killing germs

Systems used in biomedicine, purification of air, water, and food, and polymer curing and biochemical identification require the use of UV light with wavelengths in the range of 250–300nm. Currently, the primary light sources for these UV-C wavelengths are mercury lamps and gas lasers, which are big and bulky and require high voltages for their operation. The use of mercury also leads to significant environmental concerns. As a result, intense research activity has focused on replacing these conventional UV-C light sources with solid-state microdevices based on semiconductors, which would have potential advantages in terms of size, cost, and efficiency.