Graphene Edge Identification via Low-Scan-Rate AFM under Ambient Conditions

The contrast of atomic-scale images in lateral force microscopy (LFM) is strongly affected by thermal drift and the finite response time of the AFM feedback loop. When slow-scan sample drift is significant, atomic stick-slip patterns recorded along the fast-scan axis can accumulate in the slow-scan direction, resulting in elongated groove-like features rather than discrete lattice points. A previous study^[1] recommended scan rates of 25–30 Hz to minimize drift-induced distortion, but such rates can stress flexure stages and compromise image stability. To address these limitations, we investigated the effects of scan rate and feedback parameters on lattice visibility in LFM of two-dimensional materials. By optimizing scan rate, pixel density, and feedback gain, and implementing a controlled pre-scan procedure, atomic lattices were resolved at scan rates as low as 15 Hz. This method allows identification of graphene edge orientations under ambient conditions.

[1] Nanomaterials 2022, 12(9), 1542