The difference should be that SEM, TEM and AFM are more and more advanced, and the magnification is higher and higher. Xrd and infrared spectrum are irrelevant. XRD is to test the crystal structure and can tell you what your material is. Infrared reflects the characteristics of molecular structure through the position and intensity of infrared absorption peak, which can be used to identify the structural composition of infrared spectrum of unknown liquid water or determine its chemical groups. The absorption intensity of absorption band is related to the content of chemical groups, which can be used for quantitative analysis and purity identification. L infrared is mainly used to identify the structure of organic compounds in many fields such as organic chemistry, biochemistry, pharmacology and environmental science.