Size effect on compression properties of GaN nanocones examined using in situ transmission electron microscopy

Mechanical property measurements of single nanocones are challenging because the small scale of the nanostructures. In this study, critical-stress- and strain-induced structural variations of GaN nanocones are estimated using in situ transmission electron microscopy (TEM) compression experiments. For single GaN nanocones with a diameter of 100-350 nm, the Young's modulus, plastic deformation energy (Wp), and elastic deformation energy (We) values were 190-290 GPa, 0.02-1.65 × 10−11 J, and 0.04-3.85 × 10−11 J, respectively. Raman spectra were used to measure GaN indentation. The E2 peak was red-shifted, indicated increased compressive stress in the indented area.