J. Opt. 14, 125001 (2012)

Researchers in Turkey have fabricated a visible-wavelength photodetector from layers of silicon and silver nanocrystals dispersed within a polymer. Sabri Alkis and co-workers from Bilkent University say that their device has a peak sensitivity at around 600 nm and a low dark current of approximately 30 mA cm−2. The role of the silver nanocrystals is to create plasmon resonances, which enhance the absorption of light in the device. The layers of silicon and silver nanocrystals are separated by thin insulating films to reduce any current leakage. Previous detector designs have used silicon nanocrystals fabricated by chemical vapour deposition — a costly process that must be performed under vacuum conditions. This new approach, in contrast, can produce 20–150-nm-sized silicon nanocrystals using laser ablation, which is potentially a low-cost and high-throughput method. In addition to proving beneficial for making photodetectors, silicon nanocrystals made in this manner could be useful for creating a variety of other optoelectronic devices, such as flexible and disposable sensors or cost-effective solar cells.