Semiconductor nanoparticles called quantum dots are used in modern electronic displays. Quantum dots possess excellent luminescent properties but electrons behave differently in quantum dots than in bulk semiconductors. Quantum dot displays work by relying on their photoluminescence properties. In this process, they react to irradiation by ultraviolet or visible radiation by responding with their own light in a different spectral range.
Various semiconductors such as CdSe are used for manufacturing quantum-dot based displays. As these materials are expensive and toxic, researchers have been trying to utilize silicon as an alternative. Unfortunately, silicon nanoparticles only respond to radiation slightly, which does not really help the optoelectronic industry. Since the beginning of the 1990’s, researchers internationally have been attempting to find a solution, but no meaningful progress has been made thus far.
One recent idea originating from a post-doctoral researcher, Sergey Dyakov (a graduate of the MSU Faculty of Physics and the first author of the paper) at the Royal Institute of Technology, Kista, is showing promise. Dyakov suggested placing an arrangement of silicon nanoparticles in a matrix together with a non-homogeneous dielectric medium. The array was then covered with golden nanostripes. This arrangement induce the silicon nanoparticles to glow in response to radiation stronger than what they normally would.
Maxim Shcherbakov, a researcher at the Department of Quantum Electronics of the Moscow State University and one of the authors of the study, believes the resultant radiation is strong enough to be viable in the replacement of expensive semiconductors used in electronic displays. Shcherbakov also notes that other experiments conducted previously proved that the heterogeneity of the environment increases the photoluminescence of silicon by several orders of magnitude. This is due to quantum confinement. The efficiency of the light interaction with nanocrystals is however still insufficient.
Plasmons are quasiparticles appearing from fluctuations of the electron gas in metals. The team plans to use plasmons to improve this efficiency by forming a lattice with golden nanostripes. The lattice will increase the silicons’ luminescence by allowing a more effective interaction with nanoparticles located in the vicinity.
MSU experimented with samples of a gold plated matrix with silicon nanoparticles made in Sweden. The result was that the UV irradiated silicon shone so brightly that it could be used practically for the first time.
Full study has been published in the Physical Review B journal.