NMR tool allows analysis of nanometre-sized samples

The development, claimed to be a world first, is expected to reveal nanostructures at unprecedented levels of detail, opening up new areas of research and development, and device fabrication processes.

‘It is a unique technique,’ said Dr Evgeny Chekhovich from Sheffield University’s Department of Physics and Astronomy. ‘We demonstrate its capacity by measuring NMR spectra of single-strained semiconductor structures — quantum dots — something that was impossible prior to our work.’

Chekhovich explained via email that strained quantum dots have been widely investigated in the past two decades for concepts such as quantum computation and communication, quantum light sources, and solar cells.

Testing techniques

‘Naturally, structural testing techniques of strained semiconductor structures, especially non-destructive techniques such as NMR, are of great interest,’ he said.

Chekhovich explained that NMR probing involves exciting a sample with an oscillating magnetic field generated by a coil.

‘The effect of this excitation on the sample is then detected,’ he said. ‘The frequency of the radio field is then changed and its effect is measured again. This way the response of the sample as a function of frequency — namely the NMR spectrum — is measured.