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The morphology of nanosize hydrogenated crystalline silicon (nc-Si:H) films have been investigated by scanning tunneling microscopy (STM) without hydrofluoric acid etching under atmospheric conditions. Images from submicrometer scale down to atomic scale have been represented. On a large scale, the nc-Si:H films are found to be consisted of microcrystallites separated by different interfacial regions from STM results. The mean size of microcrystallites is about 3–5 nm, which is in agreement with high-resolution electron microscopy studies. In addition, near-atomic resolution STM images provide some information on the interfacial region, which seems to be crucial for the atomic structure and many properties of nanocrystalline materials. The results show that the arrangements of the atoms on nanocrystallites are well ordered, while atoms in the interfacial regions are randomly distributed. The mechanism for imaging nc-Si:H is discussed.

The brittle fracture surfaces of titanium aluminide were investigated by the scanning tunneling microscope in the range of nanometers. The results showed that there were some river marks and/or fan patterns, ditches, dimples, and cleavage steps on the cleavage fracture surfaces. This was similar to that observed by the scanning electron microscope. The height and width of the cleavage step and the dimple size were in nanometer or quasiatomic scale.

The brittle fracture surfaces of Ti3Al+Nb and Ti3Al were investigated with a scanning tunneling microscope (STM) under ambient conditions using a mechanically cut platinum iridium alloy wire and electrochemically etched tungsten tips. The results show that the fracture surfaces consist of cleavage steps with dimensions of the order of ∼2 nm for Ti3Al+Nb and ∼60 nm for Ti3Al, similar to cleavage surfaces observed by scanning electron microscopy. Some cavities between the microcleavage steps on the scale of a few nanometers were observed for Ti3Al+Nb. The reproducibility of the STM images under ambient conditions depends on the applied bias voltage. The quality of the STM images obtained via tungsten tips is better.