Figure 3
(a) The Raman spectrum of DH NM with the exciting laser spot on the NM and on the edge of NM. (b) SEM image of an N-polar NM with diagonal via spacing of 25 µm (c) Spatial mapping of intensity ratio of the A1 (TO) to E2 (high) peak. The scanning area is 60 × 60 µm2, indicated by red square in (b).
