coarse approach using the piezo motor

Put the lid onto the STM. Use the lens inside the tip and the arrow button in the approach panel to move the sample towards the tip (see fig 7).

Figure 7: The approach panel provided by the EASYSCAN software

Use the mirror image of the tip on the sample surface to adjust the position of the sample. Take time. Do not move the sample too close! If the tip crashes into the sample, a new tip has to be prepared. The LED on the STM provides information on the status of the approach:

• orange means that the sample is too far away from the tip to detect a tunneling current
• green means that the sample is well-positioned, a tunneling current is detected. This colour only appears after step 3, fine approach using the piezo motor
• red means that you have crashed the sample into the tip (you need to call the experimental supervisor).