New nanoscale parameter resolves silicon dilemma

The new discovery by Aalto University could have a major impact on future nanoscale device design, such as ultraviolet photo detectors and drug delivery. In bulk, many materials like silicon are as brittle as glass. For nanoparticles, the same material can be compressed into half the size without breaking. The new discovery was made by an international research group led by Professor Roman Nowak from Aalto University.

 

Atom by atom, the researchers followed the rearrangements resulting from squeezing tiny spheres of silicon. They found that the response of the material varied depending on the degree of deconfinement that contrasts the well known “size effect”. Shrinking the size of material volumes drives unexpected deformation mechanisms under mechanically induced shape changes.

 

In its bulk form, silicon is known to display plasticity characterized by phase transformations. However, the research found that progression from a state of relative constraint of the bulk to a less constrained state of the nanoparticle leads to a shift in silicon’s mechanical response.

 

Not a mere peculiarity, the study provides a basis for understanding the onset of incipient plasticity in nanovolumes. The succinct explanation affects future nano-devices such as ultraviolet photo detectors, lasers on a chip, drug delivery, and biological markers.

 

The introduction of the “nanoscale confinement” parameter has never explicitly been taken into account so far for size dependent phenomena. The finding resolves dilemmas noted by earlier studies and offers avenues to a broad range of nananoscale device designs. The results resolves a controversy noted in previous studies and the insight will benefit the processing of future nanostructures on a large scale.