Figure 6: Thermal resonance frequency responses; primary mode (panels (a)–(d)) and secondary mode (panels (e)-(f)) of the CCNT at different approach angles are displayed at compression distances of 250, 375, 500, and 875 nm. The approach angle was changed from 12° (green), 7° (magenta), and 2° (blue) through the use of an angled substrate. The z-piezo scan range was 2500 nm; cycles were acquired at a scan rate of 0.02 Hz.