Andor improves STL scanning with EM technology

The company, a provider of scientific imaging and spectroscopy solutions, achieved this by replacing the standard charge-coupled device (CCD) camera, used to detect photons, with one of its EMCCD cameras.

This improves the signal-to-noise ratio and cuts the time required to gather low-light-emission spectral data.

Reducing the exposure times typically associated with STL will also solve some of the common problems associated with this technique, including changes in the tip-sample cavity (through the migration of tip or sample atoms or contamination) and damage to the sample caused by excessive tunnelling current applied over a prolonged time period.

Using EMCCD Andor cameras such as the Newton(EM) model in conjunction with high-performance Shamrock spectrographs from Andor is intended to make STL a far more useful technique for applications such as characterising nanophotonic and optoelectronic devices and their structures, ultra-sensitive chemical analysis, single-molecule optical spectroscopy, single-molecule dynamics and conformational analysis, luminescence studies on quantum wells/dots, intermolecular fluorescence studies and electronic dynamics in polymers and biomolecules.

Gerald Cairns, a spectroscopy application specialist at Andor, said: 'Although STL spectroscopy is a very useful technique for generating information about the topography and structure of a sample and the chemistry of any absorbed molecules, the very low-light signals generated have necessitated the use of very long exposure times - typically several minutes.

'However, the enhanced sensitivity and higher acquisition speeds of our EMCCD cameras mean that spectral data can now be acquired far faster and with less background noise.

'This will help broaden the utility of STL and help increase our understanding of nano and microscale optoelectronic and photonic devices,' he added.