Figure 5
From: Mechanical Deformation Induced in Si and GaN Under Berkovich Nanoindentation
Raman spectra of GaN thin film taken on the pristine surface and after nanoindentation (at the corner and center of indent). Changes in Raman spectra after indentation, though displaying the effects of compressive stress, do not show clear evidence of phase transformation. The inset of Fig. 4 shows the SEM micrograph of the same area after the Berkovich indentation on GaN thin film obtained at an indentation load of 200 mN. And, no cracking is evident to be responsible for the “multiple pop-ins” observed in the load-displacement curves