1. Observation of Negative Differential Resistance Up to now, Calculation; Preparation of sample; AFM imaging.

2. At the beginning some amino silane-based molecules are used on a silicon chip. It needs to be heated to have the reaction. The flat gold substrate is made by stripping the glass glued to the gold on mica. Hexanedithiol (in ethanol) helps to bind the nanocrystals (CdSe). This is done in very diluted solutions.

3. Imaging often fails. A few are reproducible. Possible reasons: imaging is done in liquid environments, so the sample is held in a mechanically complicated way; the good engage is not achieved; the sample can be improved (annealing). To get good image is the first thing. Evaporate gold to the tip of AFM, make the conductive one. The following are some images I’ve already get.