Gold nanoparticles improve photodetector performance

Jul 26, 2013

The mineral molybdenum disulfide (MoS2), which, when solid, behaves in many ways like grease, has semiconducting properties that make it a promising alternative to silicon or graphene in electronic devices. It also strongly absorbs visible light, and so it has been widely employed in light-sensing photodetectors, which are used in a wide range of technologies, such as environmental sensing, process control in factories, and optical communication devices.

Researchers at the National University of Singapore have now found a way to boost the performance of MoS2 photodetectors even further—with nanoparticles of gold. They describe this improvement in the journal Applied Physics Letters, which is produced by AIP Publishing.

Wei Chen, an assistant professor of chemistry and physics, along with graduate student Jia Dan Lin, and their colleagues, applied a single, loosely arranged layer of to the top of a MoS2 photodetector. The gold layer, although less than 15 billionths of a meter thick (representing the diameter of each individual nanoparticle) and made up of fewer than 1000 individual particles, improved the photodetectors' efficiency by a factor of three, according to Chen.

"We anticipate orders of magnitude higher improvement of MoS2's sensitivity using a higher density of coated nanoparticles," Chen said.

Chen suspects that the plasmon oscillations (variations in the electron density) of individual nanoparticles—which enhance the local optical field—may be one reason for the improved performance of the photodetectors.

"The next step will focus on varying the materials used to make the nanoparticles, as well as their size, shape, and arrangement," Chen noted—adjustments that will "tune" the plasmon resonance wavelength of the metal nanostructure arrays, making it possible for MoS2 todetect multiple colors for the first time.

Explore further: For electronics beyond silicon, a new contender emerges

More information: Applied Physics Letters. DOI: 10.1063/1.4807658

Related Stories

Fantastic flash memory combines graphene and molybdenite

Mar 19, 2013

Swiss scientists have combined two materials with advantageous electronic properties—graphene and molybdenite—into a flash memory prototype that is very promising in terms of performance, size, flexibility ...

Recommended for you

For electronics beyond silicon, a new contender emerges

14 hours ago

Silicon has few serious competitors as the material of choice in the electronics industry. Yet transistors, the switchable valves that control the flow of electrons in a circuit, cannot simply keep shrinking ...

Making quantum dots glow brighter

16 hours ago

Researchers from the University of Alabama in Huntsville and the University of Oklahoma have found a new way to control the properties of quantum dots, those tiny chunks of semiconductor material that glow ...

The future face of molecular electronics

16 hours ago

The emerging field of molecular electronics could take our definition of portable to the next level, enabling the construction of tiny circuits from molecular components. In these highly efficient devices, ...

Study sheds new light on why batteries go bad

Sep 14, 2014

A comprehensive look at how tiny particles in a lithium ion battery electrode behave shows that rapid-charging the battery and using it to do high-power, rapidly draining work may not be as damaging as researchers ...

Moving silicon atoms in graphene with atomic precision

Sep 12, 2014

Richard Feynman famously posed the question in 1959: is it possible to see and manipulate individual atoms in materials? For a time his vision seemed more science fiction than science, but starting with groundbreaking ...

User comments : 0