Fig. 2
From: Study on ultra-high sensitivity piezoelectric effect of GaN micro/nano columns

Compressive stress test by Hysitron sample stage. a, b are the test process and result of sample 1, c, d are the test process and result of sample 2
From: Study on ultra-high sensitivity piezoelectric effect of GaN micro/nano columns
Compressive stress test by Hysitron sample stage. a, b are the test process and result of sample 1, c, d are the test process and result of sample 2