Final answer:
To study rough surfaces with STM, the quantum tunneling principle is used to map surface structures at an atomic scale, requiring very clean and smooth substrates for specimen preparation. STM images can show individual atoms, making it a powerful tool for material science and nanotechnology.
Step-by-step explanation:
To study rough surfaces using scanning tunneling microscopy (STM), one utilizes the principle of quantum tunneling of electrons between the probe and the specimen. The intensity of the tunneling current is highly sensitive to the distance between them, allowing for the mapping of surface structures at atomic resolution. Surfaces must be prepared to be very clean and atomically smooth, with common substrates being mica coated with Au(111).
Specimens are also exposed to treatments like toluene vapor to ensure they are suitably prepared for imaging. Sample images, such as those of a clean gold Au(100) surface, highlight the resolution capability of STM, showing individual atoms. In comparison, atomic force microscopy (AFM) uses a sharp probe that physically interacts with the specimen, complementing the STM in the study of surface topographies.
When studying rough surfaces with STM, scientists can gain insights into material properties like electrical conductivity and observe phenomena like surface reconstruction, which can be critical in material science and nanotechnology.