Scientists from St Petersburg University discover promising features of GaAg alloys for flexible electronics

Gallium-containing metal alloys have a wide range of practical applications, both now and soon. These include flexible robotics and medical instrumentation, as well as self-healing superconducting contacts. As miniaturisation of devices and equipment is now the general trend, it is relevant to investigate the effect of nanostructuring (i.e., size reduction to the nanometre scale) on the properties of gallium-containing alloys. To date, the effect of size reduction on phase transitions (melting and crystallisation) in such alloys has not been fully investigated. This issue appears to be of fundamental importance.

The research findings are published in Physical acoustics.

Nanostructuring of alloys can be achieved by introducing them into the pores of solid matrices with nanometre dimensions. Such matrices include porous glasses. In this research, the average pore diameter was 13 nanometres, with one nanometre being one billionth of a metre. 

‘We found a significant lowering of the melting temperature interval for nanostructured alloys of two different concentrations compared to the melting temperature of the bulk alloy. It was discovered that the crystal structures of the alloys were susceptible to changes depending on the relative concentration of gallium and silver,’ explained Elena Charnaya, Professor in the Department of Solid State Physics of St Petersburg University.

The research has been supported by the grant "Phase transformations and charge mobility in functional hybrid nanostructures with large surface area interfaces" from the Russian Science Foundation.

The scientists measured the temperature dependence of the ultrasonic velocity during cooling and heating. These measurements provided information about the change in state of the alloys under nanoconfinement conditions, i.e. with size confinement due to being in the nanometre volume. The results showed that the nanostructuring of a particular alloy can extend its use in flexible microelectronics to room temperature and below.

St Petersburg University, the oldest university in Russia, was founded on 28 January (8 February) 1724. This is the day when Peter the Great issued a decree establishing the University and the Russian Academy of Sciences. Today, St Petersburg University is an internationally recognised centre for education, research and culture. In 2024, St Petersburg University will celebrate its 300th anniversary. 

The plan of events during the celebration of the anniversary of the University was approved at the meeting of the Organising Committee for the celebration of St Petersburg University’s 300th anniversary. The meeting was chaired by Dmitry Chernyshenko, Deputy Prime Minister of the Russian Federation. Among the events are: the naming of the minor planet in honour of St Petersburg University; the issuance of bank cards with a special design; the creation of postage stamps, dedicated to the history of the oldest university in Russia; and the branding of the aircraft of the Rossiya Airlines to name just a few. Additionally, the University has launched a website, dedicated to the upcoming holiday. The website contains information about outstanding University staff, students, and alumni; scientific achievements; and details of preparations for the anniversary.