First MoS2 results

28 01 2013

This is the first of the spectra from our MoS2 experiment last week. Having peeled our layer until it was only just visible, we transferred it over on to a SiO2 covered wafer and after a quick look under the microscope we went to our Raman system. The microscope image is the inset to the image, showing the flakes we examined with Raman. The spectra shown in for the large flake in the upper centre of the image

Raman MoS2 spectra

Raman Spectra of a MoS2 flake

The peak shape is interesting, unlike previously published results, we see a higher intensity for the A1g peak in comparison to the E1g peak. As an example, the left hand hand inset is from S. Najmaei et al, (Applied Physics Letters, 100, 013106). Their work details the expected separation between the two Raman peaks and enables the determination of the number of layers. Our separation of 25.6cm-1 indicates that we have bulk material, so it would appear that in addition to enhancing the lateral dimensions of the flakes, we need to continue peeling for longer!