Fabrication and integration of monodisperse ~1 nm metal nanoparticles as charge transport islands in a device configuration remains a major challenge in the progress of SET device technology. Here, the researchers deposit AuNPs into 12 nm nanogaps between electrodes, fabricated using high-resolution e-beam lithography. The ~1 nm AuNP functions as a charge transport island within a transistor configuration and the resultant device can explore the AuNP’s quantum coulomb blockade and quantized energy level spacings at room temperature (300 K).

Quantum staircases

Tunnelling resistance is modulated to ~109 Ω by addition of a pentacene layer, allowing clear observation of quantum staircases and coulomb oscillations with an on/off current modulation ratio of ~100 observed in room-temperature current-voltage (I-V) measurements. The electron addition energy and average quantised energy level spacing is found to be 282 meV and 80.4 meV, respectively - significantly larger than the thermal energy at 300 K (25.9 meV).

This study is beneficial towards the integration of AuNPs with currently available CMOS procedures and could be a huge step toward the fabrication of room-temperature (RT) SETs for exploration of quantum electron transport at the nanometer scale. By probing the charge interaction and quantum electron transport properties, these RT operational AuNP SETs can potentially serve as ultra-sensitive single molecule detectors.

More information about this research can be found in the journal Nanotechnology 26 355204.

Further reading

Can Moore’s Law make a comeback? (Jul 2015)
Fluorescent nanoparticles for quantitative uptake studies (Apr 2015)
Tailoring zinc oxide nanowires enhances solar cell performance (Feb 2015)