Pxie 1062q

AFM measurements were performed using a commercially available AFM (NX10, Park Systems). A conductive diamond‐coated AFM tip (CDT‐FMR, NanoSensors, thermal tune‐calibrated spring constant k of ≈7.2 N m⁻¹) and Pt‐coated AFM tip (Multi75E‐G (BudgetSensors, with a thermal tune‐calibrated spring constant k of ≈4.2 N m⁻¹) were used in the experiments. The surface potential was obtained using amplitude‐modulated KPFM mode by applying a 2 V AC voltage at 17 kHz and a DC feedback voltage to the AFM tip, a scan rate of 0.5 Hz was used. The effective work function of the tip was calibrated using highly ordered pyrolytic graphite (HOPG, Park Systems). The I–V curves were measured using a function generator (PXIe‐1062Q, National Instruments) controlled through LabVIEW/MATLAB‐based software. All experiments were conducted in air with a relative humidity of ≈27% and a temperature of ≈30 °C. A silicon grating with trapezoidal steps (TGF11) for a flat‐wedge friction force calibration was purchased from MikroMasch.