Electrical contact resistance (ECR) measurements performed via conductive atomic force microscopy (C-AFM) suffer from poor reliability and reproducibility. These issues are due to a number of factors, including sample roughness, contamination via adsorbates, changes in environmental conditions such as humidity and temperature, as well as deformation of the tip apex caused by contact pressures and/or Joule heating. Consequently, ECR may vary dramatically from measurement to measurement even on a single sample tested with the same instrument. Here we present an approach aimed at improving the reliability of such measurements by addressing multiple sources of variability. In particular, we perform current-voltage spectroscopy on atomically flat terraces of highly oriented pyrolytic graphite (HOPG) under an inert nitrogen atmosphere and at controlled temperatures. The sample is annealed before the measurements to desorb adsorbates, and conductive diamond tips are used to limit tip apex deformation. These precautions lead to measured ECR values that follow a Gaussian distribution with significantly smaller standard deviation than those obtained under conventional measurement conditions. The key factor leading to this improvement is identified as the switch from ambient conditions to a dry nitrogen atmosphere. Despite these improvements, spontaneous changes in ECR are observed during measurements performed over several minutes. However, it is shown that such variations can be suppressed by applying a higher normal load.

通过导电原子力显微镜（C-AFM）执行的电接触电阻（ECR）测量具有较差的可靠性和可重复性。这些问题是由许多因素引起的，包括样品粗糙度，被吸附物污染，环境条件（例如湿度和温度）的变化以及由于接触压力和/或焦耳热引起的尖端变形。因此，即使在使用同一台仪器测试的单个样品上，ECR可能因测量而异。在这里，我们提出一种旨在通过解决可变性的多种来源来提高此类测量的可靠性的方法。特别是，我们在惰性氮气氛和受控温度下，对高度取向的热解石墨（HOPG）的原子平坦平台进行电流-电压光谱分析。在测量之前将样品退火以解吸吸附物，并且使用导电金刚石尖端限制尖端的顶点变形。这些预防措施导致测得的ECR值遵循高斯分布，其标准偏差比在常规测量条件下获得的标准偏差小得多。导致这一改进的关键因素被确定为从环境条件转换为干燥的氮气气氛。尽管有这些改进，但在几分钟的测量过程中仍观察到ECR的自发变化。然而，显示出可以通过施加更高的正常负载来抑制这种变化。在测量之前将样品退火以解吸吸附物，并且使用导电金刚石尖端限制尖端的顶点变形。这些预防措施导致测得的ECR值遵循高斯分布，其标准偏差比在常规测量条件下获得的标准偏差小得多。导致这一改进的关键因素被确定为从环境条件转换为干燥的氮气气氛。尽管有这些改进，但在几分钟的测量过程中仍观察到ECR的自发变化。然而，显示出可以通过施加更高的正常负载来抑制这种变化。在测量之前将样品退火以解吸吸附物，并且使用导电金刚石尖端限制尖端的顶点变形。这些预防措施导致测得的ECR值遵循高斯分布，其标准偏差比在常规测量条件下获得的标准偏差小得多。导致这一改进的关键因素被确定为从环境条件转换为干燥的氮气气氛。尽管有这些改进，但在几分钟的测量过程中仍观察到ECR的自发变化。然而，显示出可以通过施加更高的正常负载来抑制这种变化。这些预防措施导致测得的ECR值遵循高斯分布，其标准偏差比在常规测量条件下获得的标准偏差小得多。导致这一改进的关键因素被确定为从环境条件转换为干燥的氮气气氛。尽管有这些改进，但在几分钟的测量过程中仍观察到ECR的自发变化。然而，显示出可以通过施加更高的正常负载来抑制这种变化。这些预防措施导致测得的ECR值遵循高斯分布，其标准偏差比在常规测量条件下获得的标准偏差小得多。导致这一改进的关键因素被确定为从环境条件转换为干燥的氮气气氛。尽管有这些改进，但在几分钟的测量过程中仍观察到ECR的自发变化。然而，显示出可以通过施加更高的正常负载来抑制这种变化。在几分钟的测量过程中，观察到了ECR的自发变化。然而，显示出可以通过施加更高的正常负载来抑制这种变化。在几分钟的测量过程中，观察到了ECR的自发变化。然而，显示出可以通过施加更高的正常负载来抑制这种变化。